C-NRLF 


SB 


Boiler  Safe 

T 


ISSUED   BY    THE 


Industrial  Accident  ComnM&oft 

of  the 

State  of  California 

SAN  FRANCISCO,   CALIFORNIA 


CALIFORNIA'S  SAFETY  ORDER  SYSTEM 

BY  WILL  J.  FRENCH. 


THE  NEED  OF  BOILER  SAFETY  ORDERS. 

BY  H.  M.  WOLFLIN. 

SOME  OPINIONS  OF  THE  A.S.M.E.  BOILER  CODE. 

BY  R.  L.  HEMINGWAY. 

BOILER  SAFETY. 

BY  R.  L.  HEMINGWAY. 

HORIZONTAL  TUBULAR  BOILERS  (LETTER  AND 
CIRCULAR). 

BY  D.  C.  HARVEY. 

HOW  SAFE  IS  A  USED  LAP  SEAM  BOILER? 

EDITORIAL,  JOURNAL  OF  ELECTRICITY,  OCTOBER,  1920. 

BOILER  CODE,  THE  A.S.M.E. 

EDITORIAL,  JOURNAL  OF  ELECTRICITY,  OCTOBER,  1920. 

METHODS  OF  JOINING  BOILER  SEAMS. 

(INTERNATIONAL  STEAM  ENGINEER,  JANUARY,  1921.) 

APPLICATION  OF  INSIDE  WELT  STRAP  TO  OLD  LAP  SEAM 

BOILER. 

BY  R.  L.  HEMINGWAY. 

THE  SINGLE  SHEET  LAP  SEAM  BOILER. 

BY  J.  P.  MORRISON  (POWER,  APRIL  26,  1921). 

CHANGING  OLD  LAP  SEAM  BOILERS  TO  BUTT  SEAM 
CONSTRUCTION. 

(THE  LOCOMOTIVE,  APRIL,  1921.) 

LAP  SEAM  CRACK  CAUSES  BOILER  FAILURE 
IN  PLANING  MILL. 

(THE  BOILER  MAKER,  APRIL,  1921.) 
12180 


^sne  ^fie/emu  andwabuatfy    (oom/ianu 


ROBT.  J.  HILLAS,  President 

a 


D.  C.  HARVEY, 

Superintendent  of  Inspections 


April  29,  1921. 

ANSWER  TO  LETTER  OF 

Mr.  J.  H.  Petherick, 
Chief  Inspector, 
Balfour  Building, 
San  Francisco,  California. 

Dear  Sir  :— 

Re :  HORIZONTAL  TUBULAR  BOILERS- 
ONE  SHEET  ON  THE  BOTTOM 
TYPE  OF  CONSTRUCTION. 

Last  week  a  boiler  in  a  Saw  Mill  at  a  plant  located  in  the  south  exploded,  killing 
two  people,  injuring  several  others  and  causing  heavy  property  damage. 

At  this  writing,  complete  details  are  lacking  but  from  what  we  have  received,  the 
boiler,  which  was  of  the  Horizontal  Tubular  type,  was  constructed  with  one  sheet 
on  the  bottom  and  one  on  the  top.  The  boiler  gave  way  because  of  a  hidden  lap 
seam  crack. 

We  wish  to  obtain  at  once  a  list  of  all  such  boilers  and  the  plants  at  which  they 
are  located. 

Will  you  go  over  your  records  carefully  and  advise  us  if  you  have  any  such  boilers 
at  plants  in  your  territory  and  if  so,  the  names  and  locations.  In  addition  we  want 
to  be  advised  of  the  age  of  the  boilers. 

Read  carefully  the  instructions  with  regard  to  this  type  of  boiler  in  the  Book  of 
Inspection  Rules  and  follow  them  in  making  your  inspections.  Further  instructions 
will  be  issued  shortly. 

We  will  ask  you  to  give  us  the  information  asked  for  promptly. 

Yours  truly, 

D.  C.  HARVEY,  Superintendent. 


CALIFORNIA'S  SAFETY  ORDER  SYSTEM. 
By  WILL  J.  FEENCH,  Chairman  Industrial  Accident  Commission. 

When  the  California  Workmen's  Compensation,  Insurance  and  Safety 
Act  was  in  course  of  preparation,  a  study  was  made  of  existing  safety 
laws  in  different  states  and  countries.  The  experience  of  a  large  group 
of  other  jurisdictions  was  ascertained.  Consultation  followed  with  Cali- 
fornia employers  and  employees,  as  well  as  with  citizens  in  all  walks  of 
life.  The  consensus  of  opinion  favored  the  plan  in  operation  in  Wis- 
consin, whereby  safety  standards  were  issued  by  the  Industrial  Commis- 
sion, and  these  standards  can  be  changed  at  any  time  or  exemptions 
issued  to  meet  unusual  conditions.  The  only  other  feasible  plan  was 
that  of  having  the  legislature  definitely  state  in  statute  how  machinery 
of  all  kinds  should  be  protected.  There  could  be  little  or  no  flexibility 
under  this  plan.  Its  cost  to  California's  employers  would  have  been 
enormous,  because  there  was  no  organized  safety  movement  in  the  state 
and  the  field  was  virgin. 

The  legislature  of  1913  approved  the  plan  of  assigning  to  the  Industrial 
Accident  Commission  the  work  of  issuing  safety  standards  for  the  dif- 
ferent industries.  It  is  interesting  these  days  to  recall  the  activities  of  a 
large  group  of  employers  in  favor  of  the  plan  adopted,  because  there  were 
pending  bills  calling  for  specific  safety  installations  that  were  drastic  in 
character. 

It  is  a  fair  question  to  ask  the  experience  of  the  intervening  seven  and 
one-half  years  since  January  i,  1914.  About  twenty  of  the  largest  indus- 
tries are  governed  by  safety  orders.  Other  industries  will  have  their 
standards  set  just  as  soon  as  it  is  possible  for  the  Safety  Department, 
with  its  inadequate  force  and  lack  of  finances,  to  handle  the  work.  This 
doesn't  mean  that  general  supervision  has  been  impossible.  The  law 
requires  that  all  places  of  employment  shall  be  safe  for  the  employees 
therein,  and  employers  have  cooperated  with  the  Commission  in  a  com- 
mendable way. 

While  the  Commission  has  authority  to  issue  standards  of  safety  of  its 
own  preparation,  so  far  as  the  industries  are  concerned,  that  course  never 
has  been  followed.  The  law  gives  authority  to  appoint  "advisers"  to 
assist  the  Commission.  The  importance  of  participation  by  all  interested 
groups  in  considering  safety  standards  has  always  appealed  to  the  Com- 
mission, and  the  members  of  each  committee  were  selected  by  their 
respective  organizations.  In  no  instance  was  a  committee  "hand  picked." 
Letters  were  invariably  mailed  to  the  employers'  organization,  to  the 
trade  union,  and  to  different  associations  interested  in  the  industry  under 
consideration.  Employers  and  employees  predominated  on  each  com- 
mittee, and  the  engineers  of  the  Commission's  staff  only  held  one  or  two 
places.  Consequently,  tentative  safety  orders  were  issued  by  a  group  of 
men  with  special  knowledge  of  the  industry's  requirements.  They  were 
sent  broadcast  in  printed  form  for  criticism  or  suggested  change.  Public 
hearings  were  called  in  San  Francisco  and  Los  Angeles.  Legal  notices 
appeared  as  required  by  law,  but,  recognizing  the  fact  that  but  few  per- 
sons see  such  notices,  carefully  prepared  statements  of  the  contemplated 
public  hearings  were  sent  to  all  the  daily,  weekly  and  monthly  publications 
in  California,  together  with  statistical  information  about  deaths  and 
injuries  in  the  industry. 

M92897 


4  BOILER    SAFETY   BULLETIN. 

To  each  public  hearing  came  the  product  of  the  study  and  planning  of 
the  committee  in  the  form  of  tentative  standards.  The  experiences  of 
other  states  had  been  utilized.  The  widest  publicity  was  given  the  hear- 
ing. A  member  of  the  Commission  presided.  No  limit  was  placed  on 
speakers  in  any  way.  Each  word  of  criticism  or  recommendation  for 
change  was  taken  down  by  a  reporter  and  referred  back  to  the  committee 
that  prepared  the  tentative  orders.  An  invitation  was  extended  to  those 
interested  to  meet  with  the  committee,  in  order  that  there  should  be  com- 
plete knowledge  of  the  proposed  changes.  After  the  fullest  deliberation, 
the  committee  drafted  the  safety  orders  with  the  experience  of  the  public 
hearings  as  a  guide,  and  recommended  their  approval  by  the  Industrial 
Accident  Commission,  to  become  effective  at  a  date  in  the  future  which 
would  give  time  for  compliance.  Such  extraordinary  care  was  followed 
in  the  process  of  promulgating  each  set  of  safety  standards  that,  so  far, 
it  has  been  unnecessary  for  the  Commission  to  question  the  advisability 
of  following  the  committee's  recommendations. 

This  history  is  needed.  The  men  on  the  Industrial  Accident  Commis- 
sion and  on  its  staff  have  had,  and  still  have,  for  their  goal  reasonable 
safety,  intelligent  administration,  the  exercise  of  the  power  to  issue 
special  orders  and  grant  exemptions  when  justified,  and  a  total  avoidance 
of  what  might  appear  to  be  arbitrary  methods.  An  appeal  to  the  Com- 
mission is  always  solicited  if  an  order  is  considered  unreasonable  or  if 
there  is  objection  to  the  ruling  of  a  member  of  the  staff.  The  use  of 
home-made  guards  is  advocated.  The  reduction  of  expense  is  admittedly 
important  and  is  aided,  provided  that  safety  will  not  be  sacrificed  as  a 
result. 

The  right  hand  of  fellowship  has  been  given  the  Commission  by  a  large 
majority  of  the  employers  and  the  employees  in  California.  It  is  no  idle 
boast  to  say  that  every  effort  has  been  put  forth  to  merit  the  confidence, 
even  though  the  task  has  been  difficult  and  the  road  not  always  smooth. 
In  spite  of  these  obstacles,  it  is  felt  that  no  small  part  of  this  confidence 
has  been  earned.  While  on  the  one  hand  the  Commission  will  continue 
its  broadminded  policies,  on  the  other  hand  a  continued  and  increasing 
measure  of  cooperation  from  employers  and  employees  is  essential  for 
the  benefit  of  all. 


THE  NEED  FOR  BOILER  SAFETY  ORDERS. 

By  H.  M.  WOLFLIN,  Superintendent  of  Safety. 

After  reading  the  article  on  "The  Single-Sheet  Lap-Seam  Boiler,"  by 
J.  P.  Morrison,  on  page  26  of  this  bulletin,  it  may  be  interesting 
if  a  few  additional  facts  are  presented  concerning  the  frequency  of  boiler 
explosions  and  the  finding  of  defects  that  lead  to  such  explosions. 

In  a  pamphlet  entitled  "Steam  Boiler  Explosions,"  published  by  the 
Fidelity  and  Casualty  Company  of  New  York,  and  delivered  at  Cornell 
University  in  the  form  of  an  illustrated  lecture,  by  their  Superintendent 
of  the  Department  of  Steam  Boiler  and  Fly  Wheel  Insurance,  Mr.  Boehm 
opens  his  remarks  by  quoting  the  frequency  of  boiler  accidents  and 
"explosions,  annually  in  the  United  States.  4  He  states  ^ that  there  are 
between  13,000  and  14,000  serious  boiler  accidents,  of  which  from  300  to 


SAFETY   BUU^TIN.  J 

400  are  violent  explosions.     These  mishaps  kill  between  400  and  500  per-  ' 
sons  and  injure  700  or  800  more,  beside  destroying  over  one-half  million 
dollars  worth  of  property  each  year. 

Mr.  Boehm  then  gives  details  of  the  killed,  injured,  and  property  losses 
occurring  in  a  boiler  explosion  at  the  R.  B.  Grover  Shoe  Company,  at 
Brockton,  Massachusetts,  and  points  out  that  the  explosions  of  fire-tube 
boilers  are  more  numerous  than  those  of  water-tube  boilers.  He  also 
indicates  that  these  facts  emphasize:  (i)  The  necessity  of  constructing 
and  installing  steam  vessels  and  their  appurtenances  in  as  nearly  perfect 
a  manner  as  possible;  (2)  the  importance  of  preventing  carelessness  in 
their  operation;  (3)  the  wisdom  of  having  them  inspected  at  regular 
intervals  by  disinterested  experts;  and  (4)  the  desirability  of  forethought 
in  securing  an  adequate  amount  of  insurance  to  pay  the  loss  if  an  explo- 
sion occurs. 

He  states  that  it  is  of  the  utmost  importance  that  boilers  be  carefully" 
designed,  that  the  known  stresses  to  which  they  are  subjected  be  accu- 
rately computed,  that  suitable  material  be  specified,  that  the  material  be 
critically  examined  for  flaws  or  defects,  that  specimens  of  the  material  be 
tested  to  determine  its  strength,  that  no  abuse  of  the  material  be  allowed 
in  the  process  of  constructing  the  boiler  and  that  the  completed  boiler  be 
subjected  to  a  thorough  inspection  and  a  hydrostatic  test  before  being  put 
into  service. 

Then  follows  a  dissertation  upon  the  method  of  determining  some  of  the 
stresses  in  the  shells  of  boilers,  the  bursting  pressures,  culminating  in  the 
statement  that  "It  is  usual  in  boiler  practice  to  fix  the  allowable  working 
pressure  for  a  new  boiler  at  one-fifth  the  computed  bursting  pressure  and 
to  decrease  the  pressure  allowance  as  the  age  of  the  boiler  increases!' 

Mr.  J.  H.  Petherick,  chief  inspector  of  the  Fidelity  and  Casualty 
Company  of  New  York,  has  called  attention  to  a  letter  which  he  has  just 
received  from  Mr.  D.  C.  Harvey,  superintendent  of  inspections,  concern- 
ing a  recent  explosion  of  a  lap-seam  boiler  located  in  a  sawmill  in  the 
South.  This  is  another  instance  of  a  lap-seam  disaster  which  may  be 
added  to  the  long  list  of  boiler  accidents  resulting  from  this  method  of 
construction.  The  letter  is  dated  May  6,  1921,  and  reads  in  part  as 
follows : 

"The  boiler  was  of  the  Horizontal  Tubular  type,  66  inches  in  diameter  and  16 
feet  long.  The  age  of  the  boiler  has  not  been  determined  but  it  was  at  least  13 
years  old  and  was  constructed  with  one  sheet  on  the  bottom  and  one  sheet  on  the 
top,  with  lap  longitudinal  seams  extending  from  head  to^head.  The  seams  were 
inaccessible  for  inspection  on  account  of  the  tubes  on  the  inside  and  the  brickwork 
on  the  outside.  The  boiler  exploded  violently,  killing  two  men,  injuring  several 
others  and  causing  heavy  property  damage.  The  explosion  occurred  in  the  early 
morning  between  five  and  six  and  just  as  the  plant  was  being  gotten  ready  for  the 
day's  run,  and  our  advices  are  that  the  steam  pressure  on  the  boiler  was  about  80 
pounds. 

"The  explosion  was  due  to  a  hidden  lap-joint  crack  developing  about  18  inches 
from  the  front  head  on  the  left  side  of  the  boiler.  The  crack  was  about  2  feet  long. 
The  initial  rupture  took  place  at  this  crack  and  extended  for  6  feet  through  the 
net  section  of  the  seam,  then  for  another  6  feet  through  the  solid  plate  to  rear  head. 

"The  boiler  opened  up  flat,  shearing  the  rivets  in  rear  head  seam  and  breaking 
the  front  head  into  three  places,  also  breaking  the  cast  iron  manhole  frame  in 
several  places. 

"The  six  other  boilers  adjacent  to  the  one  that  exploded  were  knocked  off  the 
settings  and  the  building  was  entirely  demolished. 

"The  explosion  of  this  boiler  is  another  striking  instance  of  the  unreliability  of 
the  lap-seam  type  of  construction." 
2—12180 


6  BOMR   SAFETY   BULLETIN. 

Referring  once  more  to  Mr.  Boehm's  address,  I  quote  from  page  nine : 

"Besides  our  ignorance  of  the  dependable  strength  in  all  parts  of  the  plate,  there 
is  also  our  ignorance  of  the  character  of  the  workmanship  in  the  boiler.  We  can 
not  be  certain  that  all  rivet  holes  come  fair,  or  that  incipient  cracks  have  not  been 
set  up  by  an  abuse  of  the  material  during  the  process  of  construction. 

"It  is  seen  therefore,  that  factors  of  safety  are  really  made  up  of  two  parts — one 
part  a  true  factor  of  safety,  the  other  a  pure  factor  of  ignorance.  //  this  matter 
were  better  understood,  boiler  owners  would  themselves  insist  upon  a  computed 
factor  of  safety ^  of  not  less  than  -five  and  they  would  not  be>  so  persistent,  as  many 
are,  in  demanding  that  their  boiler  insurance  company  grant  an  unwise  increase  of 
pressure." 

The  remainder  of  the  address  is  devoted  to  an  explanation  of  some  of 
the  causes  of  boiler  explosions,  the  time  required  to  attain  pressure  suf- 
ficient to  rupture,  and  an  explanation  of  the  energy  stored  in  the  hot 
water  in  boilers. 

There  follows  an  interesting  quotation  from  a  book  entitled  "A  Manual 
of  Steam  Boilers,  their  Design,  Construction  and  Operation,"  by  Pro- 
fessor R.  H.  Thurston,  who  was  in  his  day  one  of  the  foremost  authorities 
on  this  subject.  On  page  645,  Professor  Thurston  says: 

"The  experience  of  the  steam-boiler  inspection  and  insurance  companies  indicates 
that,  in  the  United  States,  not  less  than  a  half,  often  two-thirds,  of  the  boilers 
inspected  may  be  expected  to  be  found  more  or  less  defective  and  perhaps  ten  per 
cent  in  a  dangerous  condition.  Of  the  boilers  which  are  not  subject  to  constant 
supervision  and  frequent  inspection  nearly  all  may  be  assumed  to  be  defective,  and 
a  large  percentage  dangerously  so." 
L 

As  tending  to  substantiate  the  claim  of  Professor  Thurston,  I  quote 
statistics  of  the  Hartford  Steam  Boiler  Inspection  and  Insurance  Com- 
pany, published  in  their  quarterly  magazine  The  Locomotive :  In  the  year 
1920  this  company  made  complete  internal  inspections  of  393,900  boilers, 
they  found  1139  of  them  uninsurable,  and  the  inspectors  discovered 
212,739  defects,  of  which  23,063  were  rated  as  dangerous.  To  show  that 
these  statistics  for  one  year  are  not  abnormal,  but  represent  a  fair  average 
over  a  number  of  years,  I  also  quote  the  complete  figures  of  the  Hartford 
Company  since  the  year  1866  up  to  December,  1920.  In  the  54  years 
included,  this  company  made  3,832,669  complete  internal  inspections, 
•condemned  29,978  boilers  and  discovered  5,492,424  defects,  of  which 
603,683  were  considered  dangerous.  These  figures  may  be  substantiated 
by  referring  to  page  184  of  the  April,  1921,  issue  of  The  Locomotive. 

From  the  foregoing  the  need  of  careful  boiler  inspection  is  apparent. 
Unless  standards  are  developed  for  these  inspections  there  will  be  a  wide 
variation  between  the  findings  of  individual  inspectors.  The  possibilities 
of  these  variations  have  become  increasingly  evident,  as  shown  by  the 
records  of  the  Department  of  Safety  which  is  responsible  for  the  inspec- 
tion of  some  3,500  uninsured  boilers  each  year.  If  it  is  difficult  to  secure 
uniformity  among  relatively  few  men  inspecting  boilers,  where  they  are 
working  under  the  immediate  supervision  of  one  man,  certainly  there  will 
be  greater  difficulty  in  securing  uniform  practices  in  inspection,  operation 
or  construction  of  boilers  where  the  work  is  performed  under  the  super- 
vision of  many  different  individuals.  To  assist  in  securing  this  uniform- 
ity and  thus  increase  the  safety  of  employees,  with  a  minimum  of  hardship 
on  employers,  a  practical,  workable  set  of  safety  orders  covering  these 
points  was  prepared  and  made  effective  in  California,  some  four  and  one- 


BOILER   SAFETY   BULLETIN.  7 

half  years  ago.  Each  year  since  that  time  some  20,000  boilers  have  been 
inspected  under  the  provisions  of  these  standards.  Not  only  has  this 
experience  shown  beyond  question  the  need  for  the  Boiler  Safety  Orders, 
from  the  standpoint  of  safety,  but  it  also  has  indicated  the  desirability  of 
making  a  few  minor  changes  in  their  provisions.  These  changes  are 
under  way. 


SOME  OPINIONS  OF  THE  A.S.M.E.  BOILER  CODE. 

By  R.  L.  HEMINGWAY,  Chief  Boiler  Inspector. 

Another  article  in  this  bulletin  gives  a  brief  history  of  how  the 
A.S.M.E.  Boiler  Code  came  to  be  drafted.  It  may  be  of  interest  to  many 
of  our  readers  to  learn  how  this  code  is  regarded,  not  only  by  those  who 
drafted  it,  but  by  others  who  are  concerned  in  its  application,  and  still 
others  whose  opinions  of  a  technical  engineering  specification  of  this 
kind,  if  the  opinion  of  experts  is  to  carry  any  weight,  must  convince  even 
the  most  skeptical  of  the  absence  of  selfish  motives  in  the  preparation  of 
the  code. 

Hitherto,  in  dealing  with  scientific  subjects,  it  has  been  common 
practice  for  individuals  to  record  the  results  of  their  observations,  experi- 
ments, experiences  and  knowledge  gained  through  years  of  research,  in 
the  form  of  individual  books.  Such  books,  while  of  immense  value  to 
those  interested  in  the  subject  covered,  seldom  carried  the  weight  that 
does  the  A.S.M.E.  Boiler  Code.  This  code  is  not  an  expression  of 
opinion  of  one  man,  resulting  from  individual  effort,  but  represents  the 
combined  views  of  many  of  the  recognized  highest  authorities  in  the 
United  States.  It  goes  even  further,  since  the  committee  that  drafted 
this  code  was  not  content  to  accept  the  views  of  Americans  and  American 
practice  alone,  but  sent  one  of  their  members  to  Europe  where  an  exhaus- 
tive investigation  of  the  government  rules  of  European  countries  was 
made,  in  order  that  this  American  Society  of  Mechanical  Engineers' 
Boiler  Code  might  not  fall  short  of  the  high  aim  that  the  individuals  on 
the  committee  desired  to  attain  when  they  undertook  this  work  of 
universal  value. 

The  society  in  the  past  has  given  to  the  engineering  profession  a  great 
deal  of  information  that  has  been  of  immense  value,  and  all  of  it  is  dis- 
seminated broadly  among  its  14,000  members  without  extra  charge.  It 
is  doubtful,  however,  if.  any  work  that  the  society  has  ever  undertaken  is 
of  more  value  or  of  greater  importance  than  this  boiler  code,  representing 
as  it  does  the  last  word  in  steam  boiler  specifications  and  assuring  to  the 
United  States  that  freedom  from  preventable  boiler  explosions  which 
European  countries  have  long  since  attained.  There  can  be  few,  if  any, 
who  will  deny  that  the  record  of  boiler  explosions,  with  the  accompanying 
loss  of  life  and  property  in  the  United  States,  is  a  strong  indictment 
against  this  country  for  its  lack  of  progress  and  its  failure  to  keep  abreast 
of  the  times. 

One  of  the  keynotes  of  modern  progress  is  conservation,  whether  it  be 
of  natural  resources  or,  equally  as  important,  human  life.  Next  in 
importance,  probably,  comes  property.  The  possibility  of  immense  loss 
to  both  human  life  and  property  that  may  occur  from  the  sudden  release 
of  the  pent  up  forces  contained  in  the  modern  steam  boiler  are  hardly  ever 


8  BOILER   SAFETY   BUIXETIN. 

realized  by  the  layman,  and  it  is  difficult  to  bring  home  to  the  non- 
technical mind  any  idea  of  the  immensity  of  these  forces. 

The  boiler  code  of  the  American  Society  of  Mechanical  Engineers  is 
designed  to  safely  control  these  forces  and  if  it  did  nothing  more,  it  has 
performed  a  service  that  commands  the  gratitude  and  respect  of  the  entire 
nation. 

In  the  face  of  the  facts  given  above,  and  they  are  incontrovertible,  it  is 
surprising  to  find  that  efforts  have  been  made  to  combat  the  continuance 
in  force  of  this  code  in  California.  As  soon  as  the  Industrial  Accident 
Commission  understood  that  this  attack  was  to  be  made,  a  number  of 
letters  were  written  asking  for  opinions  of  the  A.S.M.E.  Boiler  Code. 
Excerpts  from  some  of  these  opinions  will  be  found  appended.  It  is  inter- 
esting to  note  that  none  of  those  who  answered  the  letters  condemned  or 
criticized  the  A.S.M.E.  code.  The  specious  argument  adduced  by  local 
opponents  of  the  code,  to  the  effect  that  its  adoption  in  California  would 
act  in  favor  of  eastern  boiler  manufacturers  and  react  detrimentally  to 
the  industry  in  California,  will  not  stand  even  the  most  elementary 
analysis. 

Regardless  of  what  code  California  puts  into  effect,  eastern  manu- 
facturers will  build  in  competition  with  local  builders.  If  California 
should  draw  a  special  code  of  its  own,  eastern  competition  will  continue, 
but  the  boiler  users  of  California  will  pay  more  for  the  special  specifica- 
tions. On  the  other  hand,  if  California  should  take  the  unthinkably  retro- 
grade step  and  revert  to  the  conditions  of  placing  the  boiler  users  and  the 
employees  of  the  state  at  the  tender  mercy  of  eastern  manufacturers, 
with  no  restrictions,  then  the  local  manufacturers  will  indeed  have  cause 
for  complaint,  because  the  reputation  that  the  latter  have  earned  for 
constructing  good  boilers  of  sound  material  and  workmanship  must  be 
sacrificed  if  they  compete  with  the  unrestricted  efforts  of  eastern 
manufacturers. 

It  is  desirable,  in  a  controversy  of  this  kind,  to  limit  the  discussion  to 
the  engineering  standpoint  and  to  keep  out  all  commercial  aspects,  as  far 
as  possible.  Unfortunately,  this  desirable  condition  is  not  always  attain- 
able, and  arguments  of  a  commercial  nature  are  introduced  to  prove  that 
the  code  has  been  beneficial  to  California. 

The  largest  manufacturer  of  boilers  in  the  state,  and  the  one  having 
the  most  modern  and  up-to-date  shop,  attributes  the  success  of  his  boiler 
manufacturing  business  almost  entirely  to  the  adoption  of  this  code.  It 
is  an  undeniable  fact  that  more  boilers  have  been  built  in  California  in 
the  last  three  years  than  were  built  in  a  period  of  over  ten  years  immedi- 
ately preceding. 

Accurately  speaking,  the  boiler  code  of  the  American  Society  of 
Mechanical  Engineers  is  nothing  more  nor  less  than  an  engineering 
specification,  stipulating  the  quality  of  materials  to  be  used  in  boiler  con- 
struction, the  broad  general  principles  to  be  followed  in  construction  and 
vSetting  forth  in  simple  language  the  mathematics  that  enter  into  the  cal- 
culations necessary  to  the  proper  design  of  any  type  of  boiler.  If  these 
facts  are  thoroughly  understood,  it  is  felt  that  the  objections  to  the  code 
will  be  entirely  removed. 


BOILER   SAFETY  BULLETIN.  9 

OPINIONS  OF  THE  A.S.M.E.  CODE. 
United  States  Bureau  of  Standards. 

"The  Bureau  regards  the  Boiler  Code  of  the  American  Society  of 
Mechanical  Engineers  as  the  most  authoritative  publication  on  the  sub- 
ject of  safety  in  the  construction  and  operation  of  steam  boilers,  that  is 
available. 

"The  Bureau  of  Standards  is  very  glad  to  endorse  the  work  of  the 
American  Society  of  Mechanical  Engineers  in  this  field  and  we  hope 
that  these  standards  will  become  national  throughout  the  country." 

W.  W.  Hanscom,  Chairman,  San  Francisco  Section,  A.S.M.E.'. 

"It  has  long  been  recognized  that  standardization  in  manufacturing  is 
a  most  important  factor,  especially  where  the  products  are  to  be  of 
national  use  and  are  liable  from  the  nature  of  their  application  to  be 
dangerous  to  life  and  property  if  neglected  or  improperly  handled.  I 
know  of  no  product  to  which  this  statement  will  apply  with  more  force 
than  in  the  case  of  steam  boilers,  for  in  their  use  forces  are  constantly  at 
work  to  decrease  the  original  strength  and  factor  of  safety.  In  the 
manufacture  of  boilers,  like  every  other  product,  there  are  some  who 
take  advantage  of  every  opportunity  to  reduce  cost,  not  always  with  the 
idea  of  maintaining  safety  in  use,  but  generally  with  the  idea  of  increas- 
ing profit  at  the  expense  of  the  purchaser. 

"In  summing  up  what  has  been  previously  written,  it  would  be  evident 
that  there  is  sufficient  and  immediate  demand  for  standard  rules  regulat- 
ing the  construction,  installation  and  operation  of  steam  boilers.  That 
these  rules  should  be  nationally  adopted  and  enforced  so  that  conditions 
will  be  uniform  throughout  the  country ;  that  proper  provision  should  be 
made  for  the  depreciation  and  deterioration  continually  taking  place  in 
the  boiler  and  on  it,  to  allow  for  the  misuse  and  the  invisible  and  visible 
changes  taking  place  in  the  materials  of  the  boilers  and  also  for  the  utter 
impossibility  of  ever  reaching  100%  efficiency  in  the  manufacture  of 
materials,  the  working  of  them  into  commercial  shape,  or  in  the  use  of 
the  finished  product  in  the  service  of  man. 

"As  the  fundamental  basis  upon  which  the  Code  has  been  formulated  is 
safety,  one  of  the  principal,  if  not  the  principal,  factors  is  undoubtedly 
that  which  determines  the  allowable  pressure  at  which  a  boiler  should 
be  operated." 

Charles  Edward  Lucke,  Professor  of  Mechanical  Engineering, 
Columbia  University: 

"You  may,  therefore,  assure"  everybody  that  no  better  basis  exists,  nor 
is  there  any  prospect  of  securing  a  better  basis  for  a  safe  procedure 
regarding  boiler  construction  and  maintenance  than  is  now  available  in 
the  A.S.M.E.  Boiler  Code.  *  *  *  Just  how  to  make  a  boiler  safe 
and  how  to  prescribe  rules  insuring  its  safety,  the  Code  sets  forth  that  it 
was  framed  by  people  who  knew,  and  it  would  be  difficult  and  very  likely 
impossible  to  find  any  group  of  people  better  able  to  do  what  has  been 
done." 

S.  F.  Jeter,  Chief  Engineer, 

Hartford  Steam  Boiler  Inspection  and  Insurance  Company: 
"As  an  engineer  who  is  interested  first,  last  and  always  in  the  steam 
users'  viewpoint  relating  to  questions  regarding  rules  and  regulations  to 


10  BOILER    SAFETY   BULLETIN. 

govern  boiler  operation,  I  can  not  see  how  any  organization  is  better  fitted 
to  draft  safety  rules  than  the  American  Society  of  Mechanical  Engineers. 

"The  rules  were  adopted  only  after  the  utmost  publicity  and  an 
invitation  to  every  one  interested  to  criticise  the  proposed  rules  before 
they  were  actually  made  a  part  of  the  Code. 

"As  a  final  check  against  the  adoption  of  any  rule  that  might  react 
against  the  steam  user  or  was  not  consistent  with  good  practice,  and  as  an 
aid  in  securing  uniformity,  a  Conference  Committee  to  the  Code  Com- 
mittee was  appointed  by  the  Society,  this  Conference  Committee  being 
composed  of  the  chief  inspectors  of  all  the  states  having  adopted  the 
Code." 

F.  R.  Low,  Editor,  "Power": 

"The  specifications  are  no  more  exigeant  than  is  necessary  to  insure 
safety,  and  any  boiler  shop  can  build  to  conform  to  them.  The  conten- 
tion on  the  part  of  those  who  would  prefer  to  take  a  chance  upon  a 
boiler  that  was  not  so  safe,  that  the  Code  has  been  formulated  by  the  big 
boiler  builders  so  as  to  put  the  small  builders  at  a  disadvantage,  is  natural 
but  cheap  and  fatuous." 

John  A.  Stevens,  Chairman,  Boiler  Code  Committee,  A.S.M.E.: 

"The  A.S.M.E.  Code  is  and  was  certainly  at  the  time  of  the  convention 
the  most  complete  code  in  existence  for  the  safe  and  commercial  con- 
struction of  boilers  in  the  United  States  of  America,  as  evidenced  by  the 
number  of  states  and  municipalities  which  have  since  made  this  Code  a 
law  on  their  statute  books." 

S.  J.  Williams,  Secretary-Chief  Engineer,  National  Safety  Council: 

"I  have  no  hesitation  in  saying  that  the  A.S.M.E.  Boiler  Code  is  by 
far  the  best  code  in  existence  and  is  so  recognized  by  a  great  majority  of 
boiler  owners  and  users,  government  authorities,  and  engineers.  This 
Code  was  formulated  by  a  joint  committee  under  the  auspices  of  the 
American  Society  of  Mechanical  Engineers.  This  society  is  entirely  free 
from  any  selfish  interest  in  the  matter,  its  only  desire  being  to  standardize 
boilers  in  the  interest  of  safety,  and,  secondarily,  of  economy." 

H.  W.  Mowery,  President,  American  Society  of  Safety  Engineers: 

"The  A.S.M.E.  Code  is  a  Safety  Code.  In  the  original  statement  of 
the  Committee  to  the  Council  of  the  A.S.M.E.,  it  stated:  'The  primary 
hope  of  these  rules  is  to  secure  safe  boilers/  5: 

W.  F.  Durand,  Stanford  University: 

"Prom  such  contact  as  I  have  had  with  the  Code,  I  have  been  impressed 
with  the  fact  that  it  seemed  designed  throughout  to  promote  safety  in 
industrial  establishments,  and  to  hold  up  to  boiler  makers  and  users  a 
high  standard  of  construction  and  installation. 

"The  ideal  before  the  Society  (A.S.M.E)  in  promulgating  this  Code 
was  to  place  before  the  builders  and  users  of  boilers  a  standard  code, 
reasonable  in  its  requirements,  undeniably  safe  and  which  might  ulti- 
mately become  the  universally  recognized  standard  throughout  the 
country." 


SAFETY   BULLETIN.  II 

J.  C.  McCabe,  Chief  Inspector,  State  of  Michigan: 

''The  essential  feature  in  the  adoption  of  the  A.S.M.E.  Boiler  Code  is 
that  under  a  code  of  recognized  standing,  having  the  authority  of  the 
greatest  engineering  society  in  the  world  as  its  sponsor,  it  removes  any 
reasonable  doubt  as  to  the  safety  of  a  boiler  built  under  its  rules. 

"I  have  been  in  constant  touch  with  the  development  of  the  A.S.M.E. 
Boiler  Code,  and  the  only  criticism  which  I  can  make  against  the  Boiler 
Code  Committee  is  that  they  are  endeavoring  to  make  the  provisions  of 
the  Code  as  reasonable  as  possible,  and  occasionally  they  overstep  what 
would  be  considered,  in  my  opinion  at  least,  good  engineering  practice,  all 
with  the  best  intent  of  making  the  Code  workable,  popular  and  effective. 

"It  would  certainly  be  a  step  in  the  wrong  direction  if  the  authorities 
recede  from  their  endorsement  and  use  of  the  A.S.M.E.  Code  in  the  State 
of  California." 

Chas.  T.  Main,  Engineer,  Boston: 

"When  the  Boiler  Code  Committee  of  the  American  Society  of 
Mechanical  Engineers  was  set  up,  the  members  were  very  carefully 
selected  to  represent  equally  the  manufacturers,  users,  and  designers,  and 
that  proportion  of  members  has  been  carefully  maintained  since  that  time, 
so  that  no  one  interest  has  ever  dominated  the  committee  in  the  past,  nor 
does  in  the  present." 


BOILER  SAFETY. 

By  R.  L.  HEMINGWAY,  Chief  Boiler  Inspector. 

The  Workmen's  Compensation,  Insurance  and  Safety  Act,  effective 
January  I,  1914,  gives  to  the  Industrial  Accident  Commission  authority 
to  inspect  all  places  of  employment,  to  require  reasonable  safety  in  such 
places  of  employment,  and  for  the  purpose  of  determining  what  consti- 
tutes reasonable  safety,  the  act  specifically  gives  the  Commission  power 
to  set  safety  standards  and  to  establish  such  rules  and  regulations  as  may 
be  deemed  necessary  to  furnish  this  modicum  of  reasonable  safety. 
These  powers  are  very  clearly  set  forth  in  sections  51  to  72  of  the  above- 
mentioned  act. 

Since  the  statute  imposes  these  responsibilities  upon  the  Commission, 
it  naturally  proceeded  to  establish  safety  standards  and  regulations  to 
to  meet  the  requirements  of  the  various  industries.  It  will  be  very 
generally  admitted  that  no  set  of  safety  standards  could  be  complete 
unless  it  contained  rules  and  regulations  governing  the  operation  of 
steam  boilers,  for  the  very  obvious  reason  that  a  boiler,  even  though 
operating  at  low  pressure,  contains  all  the  potentialities  of  a  catastrophe, 
unless  the  pressure  it  carries  is  regulated  to  within  safe  limits  and 
unless  the  appliances  for  controlling  that  pressure  are  maintained  in 
proper  working  order,  under  the  supervision  and  care  of  men  intelligent 
enough  to  realize  the  responsibility  that  they  assume  when  taking  charge 
of  a  steam  boiler. 

In  the  natural  sequence  of  events,  the  drafting  of  safety  orders  to 
cover  boilers  that  were  already  installed  in  the  state  was  first  undertaken 
and  this  led  to  the  adoption  of  rules  governing  the  construction  and 
installation  of  new  boilers  in  the  future. 


12  BOMR    SAFETY   BULLETIN. 

The  formulation  of  any  one  set  of  safety  orders  is  a  matter  involving 
views  of  widely  separated  interests  and  in  consequence  of  this  the  Com- 
mission decided  to  adopt  the  plan  of  appointing  committees  who  would 
represent  these  numerous  interests,  and  thus  a  set  of  safety  orders  would 
be  formulated  which  would  obtain  the  maximum  of  safety  with  the  least 
hardship  to  all  parties  concerned.  Thus,  when  it  came  to  drafting  Boiler 
Safety  Orders,  interests  were  invited  to  send  representatives  who  would 
sit  on  the  committee  and  have  a  voice  in  all  its  deliberations.  To  further 
widen  the  scope  of  the  work,  two  such  representative  committees  were 
convened,  one  in  San  Francisco  and  the  other  in  Los  Angeles,  and  in  this 
manner  those  having  the  greatest  interests  at  stake,  including  employers 
and  employees,  were  fully  represented.  These  committees  met  over  a 
period  of  many  months  during  1915  and  1916  and,  as  a  result  of  their 
labors,  the  Boiler  Safety  Orders  comprising  rules  for  existing  installations 
and  a  code  for  the  construction  and  installation  of  new  boilers  were 
presented  at  public  hearings  in  the  fall  of  1916.  As  is  now  well  known, 
the  committee  decided  to  adopt  the  boiler  code  of  the  American  Society 
of  Mechanical  Engineers,  which  code  was  published  in  the  year  1914, 
after  several  years  of  earnest  work  on  the  part  of  some  of  the  foremost 
engineers  in  America.  Two  of  these  public  hearings  were  held,  one  in 
San  Francisco  and  one  in  Los  Angeles.  Both  meetings  were  largely 
attended  and  many  points  were  freely  discussed  although  it  was  remark- 
able that  but  few  changes  were  even  requested  when  explanation  was 
given  of  the  why  or  wherefore  in  each  case.  In  no  case  was  the  change 
or  amendment  of  more  than  minor  import. 

The  need  of  such  a  standard  code  was  becoming  more  and  more 
obvious,  as  individual  states  in  their  desire  for  progress  saw  the  necessity 
of  having  some  regulation  governing  the  construction  of  new  boilers. 
Massachusetts,  the  pioneer  state  in  this  respect,  had  a  code  of  its  own  and 
when  Ohio,  two  or  three  years  later,  decided  to  adopt  a  code,  It  was 
found  that  there  were  some  features  in  the  Massachusetts  code  that  did 
not  appeal  to  the  engineers  in  Ohio.  When  Michigan  followed,  a  dif- 
ference of  opinion  arose  between  the  Michigan  engineers  and  those  in 
Ohio  and  Massachusetts,  and  so  it  went  all  down  the  line,  until  the  boiler 
manufacturer  was  almost  at  his  wits'  end  to  know  how  to  comply  with 
the  various  state  codes,  which,  owing  to  their  strict  enforcement,  would 
not  permit  an  Ohio  standard  boiler  to  go  into  Massachusetts  or  a  Michi- 
gan standard  boiler  to  go  into  Ohio. 

It  is  easy  to  see  what  tremendous  financial  hardship  this  lack  of 
uniformity  was  imposing  on  the  industries  of  the  country,  and  also  since 
every  boiler,  practically,  that  was  built  in  the  shops  required  a  special 
specification,  the  cost  to  the  user  was  always  higher  than  it  need  be. 
Conditions  were  rapidly  leading  to  confusion  when  about  1907  or  1908, 
the  president  of  the  American  Society  of  Mechanical  Engineers  appointed 
a  boiler  code  committee  whose  special  object  was  to  draft  a  uniform 
code  for  the  construction  and  installation  of  stationary  boilers.  The 
original  committee  consisted  of  eight  members  and  they  in  turn  appointed 
an  advisory  committee  to  assist  them  in  the  draft  of  the  code.  The 
advisory  committee  represented  consulting  engineers,  manufacturers  of 
various  types  of  boilers  and  boiler  materials,  boiler  insurance  companies, 
agricultural  boiler  manufacturers,  boiler  users  and  the  American  Society 
of  Mechanical  Engineers. 


BOILER   SAFETY   BUU^TIN.  13 

This  code  was  finally  approved  by  the  Council  of  the  American  Society 
of  Mechanical  Engineers  in  February,  1915,  and  is  known  as  the  1914 
edition  of  the  A.S.M.E.  code.  The  committee  in  submitting  it  recom- 
mended that  a  permanent  revision  committee  be  appointed  to  undertake 
such  modification  or  revision  as  might  be  necessary,  as  the  state  of  the 
art  of  boiler  construction  advanced,  and  that  such  committee  should  hold 
meetings  at  least  once  in  two  years,  at  which  time  all  interested  parties 
might  be  heard.  This,  then,  is  the  code  which  the  Boiler  Safety  Orders 
committee  of  California  approved  and  recommended  to  the  Industrial 
Accident  Commission  for  adoption.  There  was  no  objection  raised  to 
the  adoption  of  this  code  at  either  public  hearing  on  Boiler  Safety  Orders 
in  the  fall  of  1916.  The  Commission  approved  this  recommendation  and 
the  code  became  effective  on  January  i,  1917,  together  with  the  Boiler 
Safety  Orders  relating  to  existing  installation,  which  the  committee 
appointed  by  the  Commission  had  drafted. 

During  1919  it  was  deemed  advisable  to  undertake  a  revision  of  the 
Boiler  Safety  Orders,  less  with  the  idea  of  changing  the  requirements  in 
any  respect  than  with  the  idea  of  introducing  certain  minor  matters 
which  the  previous  two  years'  experience  had  shown  would  increase 
boiler  safety  by  making  certain  orders  more  specific  and  incidentally 
would  be  advantageous  and  more  convenient  for  inspectors  who  had  to 
apply  these  rules.  The  only  serious  change  contemplated  related  to  the 
rules  governing  second-hand  boilers  of  lap-seam  construction,  and  also 
the  adoption  of  the  1918  edition  of  the  A.S.M.E.  code,  as  revised  by  the 
code  committee  in  lieu  of  the  1914  code.  In  this  manner  it  was  thought 
that  the  Boiler  Safety  Orders  relating  to  both  existing  installations  and 
new  installations  would  be  brought  up  to  date.  Certain  interests  in  the 
state  raised  objections  to  some  of  the  features  contained  in  the  Boiler 
Safety  Orders,  principally  with  reference  to  the  factors  of  safety  for  lap- 
seam  boilers  of  existing  installations  and  the  factors  of  safety  for  second- 
hand lap-seam  boilers. 

In  prosecuting  their  case,  these  objectors  brought  in  representatives  of 
labor  who,  unfortunately,  formed  an  entirely  erroneous  impression  of 
what  the  A.S.M.E.  code  is  or  what  it  purports  to  do,  the  controversy  cul- 
minating in  a  bill  being  introduced  into  the  legislature,  known  as 
Assembly  Bill  1300,  which  bill  was  designed  to  repeal  the  Boiler  Inspec- 
tion Act,  known  as  chapter  202  of  the  laws  of  1917  and  thus  take  from 
the  Industrial  Accident  Commission  the  authority  to  require  permits  for 
boiler  operation,  to  charge  inspection  fees  and  to  require  that  all  boiler 
inspectors  hold  certificates  of  competency  before  being  allowed  to  inspect 
boilers.  Some  of  the  proponents  of  the  repealing  measure  had  a  mis- 
taken impression  that  the  A.S.M.E.  code  would  be  eliminated  in  Cali- 
fornia by  the  enactment  of  Assembly  Bill  1300.  The  fact  is  that  only  by 
either  revising  the  Boiler  Safety  Orders  or  amending  the  Workmen's 
Compensation,  Insurance  and  Safety  Act  would  it  be  possible  to  eliminate 
the  A.S.M.E.  code. 

In  protesting  against  the  adoption  of  the  A.S.M.E.  code  in  California, 
the  claim  was  frequently  made  that  this  code  would  militate  against  local 
builders  and  would  favor  Eastern  manufacturers,  though  in  what  way 
was  never  made  even  approximately  clear.  An  illustrating  incident 
tending  to  controvert  this  argument  occurred  in  May,  1921,  when  a  state 
boiler  inspector  found  a  code  boiler  that  had  been  built  in  California  on  a 

3—12180 


14  BOILER    SAFETY 

Brown  hoist.  The  owners  are  a  concern  representing  Eastern  manu- 
facturers among  other  lines,  and  on  asking  why  an  Eastern  built  boiler 
had  not  been  used  to  replace  the  old  boiler  (also  built  in  the  East),  the 
inspector  was  told  the  California  built  boiler  cost  thirty  per  cent  less  than 
the  price  quoted  by  the  original  manufacturer.  The  records  in  the  offices 
of  the  Industrial  Accident  Commission  show  conclusively  that  more 
boilers  have  been  constructed  in  California  in  the  past  three  years  than 
were  manufactured  in  the  state  in  the  ten  years  immediately  preceding 
1918.  This  does  not  take  into  account  boilers  built  for  marine  service. 
In  all,  approximately  400  California  standard  boilers  have  been  built  in 
California  since  January  i,  1918. 

As  a  matter  of  fact,  the  A.S.M.E.  code  was  designed  and  formulated 
with  a  threefold  object,  viz:  (i)  Primarily  to  secure  safe  boilers;  (2) 
to  safeguard  the  interests  of  all  concerned,  especially  manufacturers  of 
boilers,  whether  in  California  or  elsewhere,  by  making  requirements 
which  were  such  that  they  would  not  entail  undue  hardship  by  departing 
too  widely  from  present  practice;  (3)  the  furnishing  of  a  uniform  code 
with  which  any  manufacturer,  whether  east,  west,  north  or  south,  could 
readily  comply. 

The  thought  in  the  minds  of  those  who  objected  to  the  code  seemed  to 
be  that  California  should  draft  a  code  of  her  own,  which  would  incorpo- 
rate certain  features  and  rules  that  would  favor  local  manufacturers  and 
enable  them  more  readily  to  compete  with  Eastern  manufacturers.  It  is 
self-evident  that  these  men  failed  to  realize  the  enormous  amount  of 
labor  and  money  required  before  such  a  code  could  be  prepared. 
Furthermore,  it  is  very  unlikely  that  such  a  local  code  would  be  as  good 
as  the  A.S.M.E.  code,  for  the  reason  that  there  would  not  be  available 
the  engineering  talent  that  was  available  for  the  latter. 

Mr.  S.  F.  Jeter,  Chief  Engineer  of  the  Hartford  Steam  Boiler  Inspec- 
tion and  Insurance  Company,  writing  on  this  subject,  in  the  July,  1916, 
issue  of  The  Locomotive  says  * 

"If  the  need  for  adopting  the  same  set  of  rules  in  each  state  where  laws  are 
proposed  to  govern  the  construction  of  boilers  is  considered  advisable — and  it  does 
not  seem  possible  that  the  least  thought  on  the  subject  can  lead  to  any  other  con- 
clusion from  the  steam  users'  standpoint — then  the  American  Society  of  Mechanical 
Engineers'  Boiler  Code  is  practically  the  only  set  of  rules  available  for  such  use. 
All  disputed  points  in  connection  with  these  rules  have  been  fought  out  with  the 
parties  interested  and  a  conclusion  reached ;  and  any  attempt  at  selecting  a  different 
set  of  rules  would  mean  that  the  same  ground  would  have  to  be  fought  over  again. 
It  is  more  than  likely  that  in  the  end  practically  the  same  conclusions  would  be 
reached,  if  a  like  amount  of  care  was  used,  as  in  the  preparation  of  the  Boiler 
Code." 

There  can  be  no  question  of  the  wisdom  in  California  adopting  this 
code  when  one  considers  the  fact  that  nineteen  states  and  twenty- four 
municipalities  have  already  adopted  it,  and  it  has  been  added  to  the  text- 
books in  many  of  our  most  prominent  engineering  colleges  and  schools. 
Once  more  quoting  Mr.  Jeter,  from  the  same  source: 

"It  would,  therefore,  appear  that  the  American  Society  of  Mechanical  Engineers' 
Boiler  Code  should  be  superior  to  any  set  of  rules  that  has  been  put  out  or  may  be 
put  out  by  a  State  Board  delegated  to  perform  a  similar  duty." 

In  his  conclusion,  Mr.  Jeter  says : 

"Since  the  steam  user  is  the  one  who  ultimately  will  derive  the  greatest  benefit 
by  the  attainment  of  the  desired  end,  in  that  he  will  secure  the  greatest  return  for 


15 

his  investment,  in  boiler  equipment,  it  would  seem  only  right  that,  as  the  project 
has  been  so  auspiciously  launched,  the  steam  users  should  lend  their  full  coopera- 
tion in  carrying  the  work  to  a  complete  and  successful  finish." 

Reverting  to  the  statement  already  made,  that  the  only  change  of  note 
in  the  revised  Boiler  Safety  Orders,  as  they  relate  to  existing  installa- 
tions, was  in  connection  with  the  factor  of  safety  for  second-hand  boilers 
of  lap-seam  construction  the  charge  was  frequently  made  that  the  revision 
of  the  Orders  was  along,lines  that  would  call  for  drastic  reduction  in  work- 
ing pressures  on  lap-searn  boilers  and  even  the  proposed  new  rules  would 
condemn  all  lap-seam  boilers  in  California.  No  statement  could  possibly 
have  been  more  remote  from  the  actual  facts,  since  the  revision  committee 
has  never  even  contemplated  changing  the  factors  of  safety  on  any 
boilers  except  the  second-hand  lap-seam  boilers,  either  by  upward  or 
downward  revision. 

Since  the  Boiler  Safety  Orders  went  into  effect  on  January  I,  1917, 
the  Boiler  Division  of  the  Department  of  Safety  has  inspected  approxi- 
mately 4,049  boilers,  of  which  number  the  records  show  only  46  were 
actually  condemned  as  being  unfit  for  further  service.  Many  of  these 
might  still  have  been  of  some  use  as  heating  boilers,  had  there  been  any 
call  for  them.  At  prevailing  junk  prices,  however,  they  were  worth 
more  to  their  owners  as  scrap.  There  were,  of  course,  numerous  cases, 
where  pressures  were  reduced  to  comply  with  the  rules,  but  these  were  in 
no  way  to  be  regarded  as  condemnations,  because  under  the  Boiler  Safety 
Orders  the  boilers  could  still  be  operated  under  a  factor  of  safety  of  5^ 
as  second-hand  boilers  after  proper  inspection. 

The  claim  was  frequently  made  that  these  factors  of  safety  for  lap-seam 
boilers  of  existing  installation  were  unreasonable  and  that  they  inflicted 
serious  hardships  on  the  owners  of  boilers  of  that  type.  It  is,  however, 
extremely  difficult  for  the  initiated,  or  indeed  for  any  one  accepting 
the  logic  of  engineering,  to  see  how  such  a  claim  could  be  made,  when  it 
is  considered  that  the  least  factor  of  safety  that  may  be  used  on  a  brand 
new  code  boiler  is  5,  and  the  Boiler  Safety  Orders  do  not  call  for  any 
higher  minimum  factor  of  safety  than  5  on  a  boiler  of  lap-seam  con- 
struction, existing  installation,  regardless  of  age  or  service,  provided  in 
the  opinion  of  an  inspector  its  condition  warrants  continuing  this  factor 
of  safety. 

One  can  hardly  believe  that  the  proponents  of  lower  factors  of  safety 
would  claim  that  a  boiler  is  less  safe  in  Massachusetts  or  Ohio  than  in 
California,  since  in  those  two  states  operators  of  boilers  are  required  to 
have  licensed  engineers  and  firemen  in  charge,  and  yet  the  factors  of 
safety  in  Massachusetts  vary  from  5  as  a  minimum  up  to  ten  years  of  age, 
5*/2  up  to  fifteen  years  of  age,  and  5^4  up  to  twenty  years  of  age,  with  6 
for  boilers  over  twenty  years  of  age,  there  being  no  exceptions  and  no 
provisions.  In  other  words,  if  a  lap  seam  boiler  in  Massachusetts  has 
passed  its  twentieth  anniversary  and  the  pressure  given  by  a  factor  of 
safety  of  6  will  not  perform  the  work  required  of  it,  that  boiler  must 
automatically  be  thrown  out,  regardless  of  its  condition,  no  provision 
even  being  made  to  allow  for  part  time  use.  The  following  table  illus- 
trates the  factors  of  safety  on  boilers  of  longitudinal  lap  seam  construc- 
tion in  some  of  the  states  that  have  boiler  rules  in  effect. 


i6 


-  B01U&   SAFETY   BULLETIN. 


FACTORS  OF  SAFETY. 


Existing  installation 

New  installation 

Longitudinal  lap  seam 

Butt  strap 
construe.  ion_, 

Second  hand 
longit.  lap 

f 

j 

f 

0 

f 

! 

Mo 

** 
\ 

..0 

r 

1.    1917    California*1 

11 

41 
41 
41 
41 
41 
5 
5 
6 

41 
41 
4| 
41 
41 
41 
41 
5 
5 
6 

tf 

4 

41 

43 
41 
41 

51 
51 
6 

5 
41 

41 
5 
5 
4| 
51 

? 

5|» 
4| 
41J 

Si" 
5i» 
41 
6 
6 
6 

4  h 
8  g 
41 
41 
4  J 
4  i 
41 
41 
41 

51 

41 

51 

51 

8  8 

8' 
6.3 

A.S  M  E     Code                5 

2.    1916    Ohioce 

A  S  M  E     Code                5 

3.    1919    Missouri 

A  S  M  E     Code            -  5 

4.    1916    Pennsylvania  

A.S.M.E.    Code  5 

5.    1920    New  York" 

A.S.M.E.    Code  5 

6.    1918    New  Jerseybe 

A.S.M.E.    Code  5 

7.    1920    Wisconsin 

A.S  M.E     Code          __  5 

8.    1910    City  of  Detroit*... 
9.    1919    Massachusetts8  
10.    1913    British  Columbia- 

A.S  M  E     Code            -  5 

Mass.  Boiler  Rules  5 
Provincial   Law...    __  k 

aFactor  of  safety  of  5  allowed  if  conditions  warrant. 

bRiveted  joints  to  be  uncovered  for  hydrostatic  test  if  factor  of  safety  5  is  continued  over  20 

years  of  age. 

cFactor  of  safety  shall  be  increased  if  the  conditions  and  safety  of  the  boiler  demand  it. 
dAllowance  in  age  made  for  part  time  use. 
eNo  allowance  in  age  made  for  part  time  use. 
'Pressure  cut  to  50  Ibs.  except  that  factor  of  safety  4J  may  be  continued  to  25  years  if  condition 

of  boiler  warrants  it. 

eFor  shells  over  36  inches  diameter  factor  of  safety  6  if  36  inches  or  less  in  diameter. 
hAfter  Jan.  1,  1922,  the  minimum  factor  of  safety  is  4J. 
'Over  20  years  of  age  the  minimum  factor  of  safety  is  41. 
JOver  10  years  of  age  the  minimum  factor  of  safety  is  4jfe. 
kThe  basic  factor  of  safety  is  4,  to  which  are  added  penalties  for  conditions  and  bad  practices 

during  construction. 

In  the  face  of  the  foregoing,  it  is  difficult  to  understand  the  reasoning 
that  actuates  men  in  asking  for  a  reduction  in  the  factors  of  safety  that 
are  stipulated  in  the  Boiler  Safety  Orders  of  January  I,  1917. 

The  question  may  be  asked,  "Why  is  it  necessary  to  discuss  at  such 
length  the  factors  of  safety  on  lap  seam  boilers?"  The  answer  is  found 
in  the  pages  of  engineering  magazines,  such  as  Pozver  and  The  Boiler- 
maker, which  report  boiler  explosions,  together  with  the  details  of  the 
causes  that  have  been  determined  upon  investigation. 

History  has  shown  that  the  boiler  with  longitudinal  lap  seams  has  a 
disagreeable  propensity  for  developing  a  hidden  crack  which  seldom 
gives  warning  of  its  presence.  Furthermore,  when  the  failure  occurs,  it- 
comes  with  a  suddenness  and  violence  that  results  in  havoc  and  destruc- 
tion all  around.  Such  a  case  occurred  in  the  Grover  Shoe  Company,  at 
Brockton,  Massachusetts,  when  58  lives  were  lost  and  117  people  were 
injured,  the  property  loss  amounting  to  over  $250,000.  In  another  part 
of  this  bulletin  will  be  found  descriptions  of  a  more  recent  boiler  explosion 
that  was  caused  by  a  lap-seam  crack. 


BOILER   SAFETY   BULLETIN.  17 


j    •/•  j 

aetefu  ana 

ROBT.  J.  HILLAS,  President 


-         1, 

of  <yVe 


D.  C.  HARVEY,  /  x 

Superintendent  of  Inspections  <sVec 

May  31,  1921. 
DCH.MAW 

CIRCULAR  LETTER  NO.  151. 

ANSWER  TO  LETTER  OF 
TO   ALL   BOILER   AND   FLY-WHEEL  INSPECTORS  : 

HORIZONTAL  TUBULAR  BOILERS. 
LAP  SEAM  TYPE  OF  CONSTRUCTION. 

HORIZONTAL  TUBULAR  BOILERS 
CONSTRUCTED  WITH  LONGITUDINAL  LAP  SEAMS 

EXTENDING  FROM   HEAD  TO  HEAD 

AS  IN  CASE  OF  ONE  SHEET  ON  THE  BOTTOM 

AND  ONE  SHEET  ON  THE  TOP  BOILERS. 


In  making  inspections  of  Horizontal  Tubular  boilers  of  the  lap  seam  type  of 
construction  twenty  years  or  more  old,  each  inspection  report,  other  than  data 
report,  should  have  written  on  it  by  the  inspector  the  following  statement:  THIS 

BOILER  IS   OF  THE  LAP  SEAM  TYPE  AND  IS YEARS  OLD. 

The  object  of  this  is  so  that  in  s-ending  out  the  report,  attention  may  be  called  to 
the  age  and  construction  of  the  boiler.  It  does  not  necessarily  follow  it  is  con- 
sidered the  pressure  should  be  reduced  or  the  boiler  replaced  by  one  of  modern 
design.  The  result  of  the  inspection  will  show  what  is  required  in  this  respect. 

It  is  important  the  assured  should  be  advis-ed  of  the  situation  and  the  reasons  for 
discarding  boilers  of  this  type  so  that  when  the  proper  time  arrives  to  reduce  the 
pressure  or  call  for  the  boiler  to  be  replaced,  they  can  not  say  the  matter  has  not 
been  brought  to  their  attention  before  we  advised  taking  action. 

Explain  to  the  assured  the  weakness  of  the  construction  and  point  out  disastrous 
explosions  have  resulted  from  the  continued  operation  of  such  boilers.  Explain  to 
them  how  a  piece  of  metal  will,  after  repeated  bending,  eventually  break.  How  a 
similar  action  takes  place  at  the  lap  longitudinal  seams  due  to  the  distortion  from 
the  true  circle. 

It  is  important  you  see  the  above  is  done. 


1 8  BOILER    SAFETY   BUU/ETIN. 

HYDROSTATIC  TESTS :  In  the  case  of  boilers  of  the  lap  seam  type  of  construction 
that  have  reached  the  age  of  20  years,  arrangements  should  be  made  for  applying  a 
hydrostatic  test  at  the  time  of  the  internal  inspections.  In  case  there  are  no  facilities 
at  the  plant  for  applying  such  a  test,  then  draw  attention  to  this  fact  on  the 
inspection  report. 

HORIZONTAL  TUBULAR  BOILERS  CONSTRUCTED  WITH  LONGITUDINAL  LAP  SEAMS  EXTEND- 
ING FROM  HEAD  TO  HEAD:  All  boilers  of  this  type  are  of  obsolete  construction  and 
should  be  looked  on  with  suspicion  and  the  inspections  should  be  most  rigid.  When 
boilers  of  this  typ'e  have  reached  the  age  of  twenty  (20)  years,  they  should  be 
replaced  and  under  no  circumstances  should  they  be  continued  in  service  unless 
subjected  to  a  hydrostatic  test  of  50  per  cent  in  excess  of  the  pressure  at  which  they 
are  to  be  operated,  with  the  brickwork  removed  to  expose  the  longitudinal  seams. 

In  making  inspections  of  this  type  of  boiler,  arrangements  should  be  made  with 
the  assured  to  apply  the  hydrostatic  test  and  to  uncover  the  longitudinal  seams 
when  this  is  done.  If  the  test  and  inspection  show  there  is  no  evidence  of  lap  seam 
cracks  or  other  weakness,  the  boiler  may  be  continued  in  service  for  a  limited 
period,  in  ord'er  to  give  the  assured  an  opportunity  to  procure  a  new  one.  The 
matter  should  be  followed  up  closely  until  the  boiler  has  been  replaced. 

The  following  factors  of  safety  should  be  us'ed  in  determining  the  allowable 
pressures : 

10  to  15  years factor  5 

15  to  20  years factor  6 

20  years  and  over factor  8 

In  making  your  inspections  if  you  find  the  factors  of  safety  as  given  above  will 
reduce  the  pressure  to  a  point  that  would  make  the  boiler  useless,  then  explain  to 
the  assured,  providing  the  age  and  condition  of  the  boiler  in  your  opinion  warrants, 
thai  at  your  next  inspection,  it  will  be  necessary  to  reduce  the  pressure  to  correspond 
with  the  factors  of  safety,  as  stated  and  in  this  manner  give  them  ample  warning 
in  advance  of  what  will  be  done  and  so  they  may  have  time  in  which  to  make 
change  that  may  be  required  to  meet  the  conditions. 

It  is  important  you  explain  to  the  assured  the  weakness  of  the  construction  of 
the  boilers,  pointing  out  the  longitudinal  seams  are  continuous  and  are  not  broken  as 
in  the  case  of  boilers  built  in  ring  courses  and  that  the  absence  of  girth  seams 
tends  to  further  weaken  the  structure. 

The  instructions,  as  outlined  above,  must  be  rigidly  adhered  to  and  we  hold  the 
inspector  responsible  for  seeing  this  is  done. 

Please  acknowledge  receipt  of  this  letter. 

Yours  truly, 

D.  C.  HARVEY,  Superintendent. 


BOMR    SAFETY   BULLETIN.  IQ 

HOW  SAFE  IS  A  USED  LAP-SEAM  BOILER?* 

The  question  of  the  factor  of  safety  to  be  used  in  determining  safe 
working  pressures  for  boilers  other  than  those  built  to  comply  with  the 
A.S.M.E.  code  and  which  have  been  for  some  years  in  operation,  has 
been  one  fraught  with  considerable  discussion  in  recent  weeks  in  the 
West.  It  seems  that  the  boiler  revision  committee  of  the  Industrial  Acci- 
dent Commission  of  California,  holding  hearings  in  San  Francisco,  pro- 
poses a  factor  of  safety  increasing  with  the  actual  use  of  the  boiler. 
Some  serious  objections  have  been  made  to  these  factors  by  users  of 
boilers  and  by  second-hand  dealers.  It  would  appear  evident  that  an 
increasing  factor  should  be  applied  from  year  to  year  in  proportion  to  the 
length  of  service  of  the  boiler,  and  it  is  to  be  hoped  that  the  objections 
will  be  cleared  away  in  a  friendly  manner  and  the  entire  code  put  into 
operation  at  the  earliest  date  possible,  in  order  that  this  commonwealth 
may  stand  in  its  usual  position,  that  of  front  rank  in  matters  of  progress 
towards  safety  and  accident  prevention. 

Lap-seam  construction  has  come  in  for  the  greatest  amount  of  dis- 
cussion. The  attitude  of  the  committee  appears  to  be  fair  to  the  owners 
of  lap-seam  boilers  within  the  state  of  California  in  that  it  proposes  no 
change  in  safety  factors  on  existing  installations  from  those  in  force 
since  January  I,  1917.  These  boilers  were  purchased  and  installed  in 
good  faith,  under  the  conditions  of  safety  then  generally  known.  But 
the  committee  seems  to  be  unwilling  to  permit  a  prospective  purchaser  to 
buy  and  change  the  location  of  a  lap-seam  boiler  which  has  already  been 
in  use,  without  applying  a  factor  of  safety  which  it  believes  reasonably 
safe  for  this  type  of  construction.  Eventually,  the  committee  feels,  the 
lap-seam  construction  must  be  displaced  by  a  design  that  is  free  from  the 
inherent  defect  known  to  boiler  experts  as  "the  typical  lap-seam  crack." 

"Second-hand  stationary  boilers  within  the  state  of  California  on 
October  I,  1920,  by  which  is  meant  boilers  where  both  ownership  and 
location  are  changed,  shall,  if  of  lap-seam  construction,  have  a  factor  of 
safety  of  at  least  six,"  says  Sec.  381,  (a)  of  the  proposed  revision. 
Virtually  identical  installations  in  other  communities  show  that  the  states 
of  New  York,  New  Jersey,  and  Pennsylvania  require  the  same  factor  of 
at  least  six,  while  Ohio,  Massachusetts  and  the  city  of  Detroit  will  permit 
nothing  under  eight,  except  for  boilers  thirty-six  inches  in  diameter  or 
under,  when  the  factor  of  safety  is  at  least  six.  It  would  seem  then  that 
a  factor  of  six  could  well  stand,  and  that  the  objections  urged  against  its 
adoption  as  being  too  high  and  as  leading  to  prohibitive  boiler  practice 
should  be  overruled. 

BOILER  CODE— THE  A.S.M.E.* 

Unquestionably  one  of  the  most  constructive  pieces  of  engineering 
work  ever  undertaken  by  an  engineering  society  is  that  of  the  boiler  code 
of  the  American  Society  of  Mechanical  Engineers.  This  code  goes  into 
great  detail  as  to  how  boilers  should  be  properly  constructed,  the  factors 
of  safety  involved  in  designing  the  boiler  and  many  other  helpful  and 
valuable  rules  for  proper  design  and  installation.  Since  the  code  was 
first  promulgated  in  1914,  seventeen  states  and  several  cities,  including 

*E)ditorial,  Journal  of  Electricity,  October  1,  1920. 


20  BOILER    SAFETY   BULLETIN. 

Philadelphia,  Detroit  and  Seattle,  have  adopted  it  as  the  official  legal 
document  for  state  inspection  work.  California  has  adopted  the 
A.S.M.K.  1914  code  as  from  January  I,  1917,  and  the  revised  boiler  safety 
orders  propose  to  adopt  the  1918  code.  The  California  Industrial  Acci- 
dent Commission  is  to  be  congratulated  on  this  forward  step  toward 
boiler  safety. 

METHODS  OF  JOINING  BOILER  SEAMS.* 

The  boiler  is  unquestionably  the  most  prolific  source  of  danger  and 
disaster  in  steam  plant  operation.  The  history  of  steam  generation  for 
power  purposes  furnishes  ample  demonstration  of  what  this  magazine  of 
stored-up  energy  can  accomplish,  in  the  way  of  general  destructiveness, 
when  once  it  breaks  out  of  bounds.  An  almost  interminable  list  of  dis- 
astrous experiences  with  defective  and  neglected  boilers  has  made  us 
thoroughly  alive  to  the  potentiality  of  this  detail  of  power  plant  equip- 
ment as  the  instrument  of  devastation  and  ruin;  and  as  a  result,  the 
boiler  has  always  been  the  theme  of  a  vast  amount  of  discussion  and 
agitation,  looking  to  general  improvement  along  the  lines  of  safe  design, 
construction  and  operation.  Indeed,  it  is  the  case  in  many  localities  and 
states  that  legislative  enactment  is  resorted  to  in  the  endeavor  to  safe- 
guard life  and  property  from  the  menace  of  dangerous  boiler  plants,  by 
compelling  vigilant  care  in  the  selection  of  correct  designs  and  the  best 
obtainable  materials,  as  well  as  in  the  items  of  good  workmanship  and 
intelligent  operating  conditions. 

The  Lap-Seam  Boiler. 

The  type  of  boiler  that  has  furnished  by  far  the  greatest  number  oi 
explosions  during  recent  years,  is  the  horizontal  tubular  boiler,  with 
boiler-riveted  lap-joints,  longitudinal  seams  and  as  a  general  rule,  it  has 
been  found  that  when  one  of  these  boilers  explodes  the  initial  rupture 
occurs  in  one  of  the  aforesaid  seams. 

While  there  is  a  constantly  growing  sentiment  among  practical 
engineers  antagonistic  to  the  lap-riveted  longitudinal  seam  and  notwith- 
standing likewise  that  boilers  with  this  type  of  seam  are  being  gradually 
legislated  out  of  existence  in  some  states,  in  favor  of  boilers  having  the 
mechanically  correct  butt-and-strap  joined  seams,  still  the  manufacture 
and  use  of  boilers  of  this  type  continues  to  go  on  unrestricted  in  most 
parts  of  the  United  States,  and  it  appears  highly  probable  from  present 
indications  that  we  will  not  see  the  end  of  this  mechanical  monstrosity  for 
some  years  to  come.  It  is,  therefore,  appropriate  that  in  this  discussion 
of  boiler  seams,  we  should  give  priority  of  attention  to  this  oldest  and 
generally  most  prevalent,  as  well  as  most  reprehensible  form  of  joint. 

The  Lap-Riveted  Longitudinal  Seam  Inherently  Defective. 

To  begin,  let  us  first  investigate  the  lap  joint  as  used  in  longitudinal 
seams,  with  a  view  of  finding  out  wherein  it  is  really  deficient,  for  a 
superficial  glance  at  the  proposition  would  indicate  that  so  far  as  the 
ordinary  stresses  of  operation  are  concerned,  this  type  of  joint  should 
be  just  as  safe  and  reliable  as  any  other ;  and  such  is  the  case,  for  by 
correctly  proportioning  the  diameter  and  pitch  of  the  rivets  and  the 

*Reprinted  from  the  January,  1921,  issue  of  International  Steam  Engineer. 


BOILER   SAFETY   BULLETIN. 


21 


thickness  of  the  plate,  to  the  tensile,  shearing  and  compressive  stresses 
involved,  a  joint  of  this  kind  may  be  designed  which  will  give  a  percent- 
age of  the  strength  of  the  solid  plate  ample  for  all  ordinary  purposes. 

The  objection  to  the  lap-joint  construction  is  not  based,  however,  upon 
any  deficiency  of  strength  when  new,  but  upon  the  deterioration  that 
immediately  sets  in,  the  very  moment  the  boiler  first  goes  into  service,  by 
reason  of  the  bending  stress  in  the  net  section  of  plate  between  the  rivets 
in  the  outer  row. 


To  make  this  point  clear,  let  us  refer  to  Figure  One,  which  represents  a 
cross-section  through  a  shell  made  of  boiler  plate  one-half  inch  thick,  and 
rolled  to  a  nominal  internal  radius  of  ten  inches. 

Now  if  this  shell  plate,  when  flattened  out,  had  been  sheared  to  the 
exact  width  necessary  to  form  the  envelope  of  a  cylinder  twenty  inches 
in  diameter,  and  had  then  been  rolled  to  conform  to  a  2O-inch  circle,  it 
would  have  met  or  butted  edge  to  edge,  and  the  internal  radius  would 
have  been  exactly  ten  inches,  no  matter  in  what  direction  it  might  have 
been  measured  from  the  axis  of  the  shell. 


22  BOILER   SAFETY 

But  in  order  to  make  a  lap  joint  for  a  shell  of  ten  inches  radius,  as 
shown  in  the  illustration,  it  is  necessary  to  cut  the  sheet  wider  than  the 
length  of  the  circumference  of  a  2O-inch  circle,  and  so,  when  the  plate 
is  rolled  to  a  lo-inch  radius  and  the  edges  slipped  by  each  other  to 
form  the  joint,  any  radius  in  the  segments  A,  B,  C  will  be  ten  inches,  or 
an  extremely  close  approximation  thereto ;  but  at  the  same  time  the  radii 
in  the  lower  half  of  segment  D  will  gradually  increase  toward  the  joint, 
while  the  radii  in  the  upper  half  will  decrease  as  they  approach  the 
joint,  the  net  result  being  that  a  radial  line  measured  to  a  point  directly 
beneath  the  joint  will  approximate  very  close  to  ten  and  one-fourth 
inches,  while  the  corresponding  radial  line  above  the  joint  will  be  nine 
and  three-fourths  inches  or  thereabouts,  the  resilience  of  the  plate  being 
assumed  as  uniform  throughout. 

Now  we  know  that  the  energy  of  an  internal  pressure  against  the  wall 
of  a  cylindrical  vessel  is  manifested  in  the  effort  to  maintain  the  true  cir- 
cular form  and  round  out  any  indentations  or  irregularities  tending  to 
impair  the  cylindrical  contour  of  the  vessel.  Consequently,  if  a  liquid  or 
fluid  pressure  were  applied  to  the  inner  surface  of  our  shell  in  Figure  One, 
through  the  agency  of  water,  air,  steam  or  otherwise,  its  energy  would 
immediately  be  exerted  in  an  effort  to  make  all  points  in  the  surface  of  the 
shell  conform  to  the  same  distance  from  the  axis,  and  the  direct  effect  of 
this  straining  after  perfect  symmetry,  would  be  to  induce  a  flexure  in  the 
seam  by  the  lengthening  of  the  radii  above  the  joint  and  the  shortening 
of  those  below.  This  bending  stress  would  obviously  expend  itself  in 
straining  the  inner  lap  through  the  section  of  metal  between  the  rivet 
holes  in  the  upper  row,  and  the  outer  lap  through  the  section  of  metal 
between  the  rivet  holes  in  the  lower  row. 

It  might  reasonably  appear  from  cursory  and  superficial  study  of  the 
phenomenon  that  the  strain  involved,  being  of  such  inconsiderable  mag- 
nitude, could  really  have  no  deleterious  effect  on  boiler  plate  possessing- 
the  highly  malleable  and  ductile  properties  required  of  first-class 
material ;  and  such  would  undoubtedly  be  the  case,  if  the  bending  of  the 
plate  in  the  places  indicated  would  occur  only  at  comparatively  long 
intervals  in  the  life  of  the  boiler,  as  for  instance,  at  the  beginning  and 
close  of  a  period  of  actual  service. 

This  advantageous  condition,  however,  can  not  possibly  be  realized  in 
boiler  practice,  for  the  maintenance  of  a  constant  steam  pressure  is  some- 
thing highly  impracticable,  if  not  to  say  impossible  of  accomplishment 
with  ordinary  method  of  operation,  and  the  aforesaid  flexure  occurs  with 
every  change  of  pressure,  howsoever  slight.  The  very  moment  a  diminu- 
tion of  pressure  occurs,  the  resilience  or  springiness  of  the  material 
instantly  responds  in  an  effort  to  restore  the  shell  to  its  original  shape, 
as  shown  in  the  illustration.;,  but  when  the  pressure  again  augments,  no 
matter  how  trivial  the  increase,  the  edges  of  the  plate  again  attempt  to 
get  into  the  line  of  strain ;  the  pulsation  being  continuous,  though 
insidious  and  never  discernible  to  the  eye.  The  alternate  movement  here 
described  is  frequently  referred  to  as  the  "breathing"  action  of  the 
boiler,  since  it  is  quite  analogous  to  the  regular  expansion  and  contrac- 
tion of  the  human  torso  under  the  stimulus  of  the  respiratory  nerves. 

It  is  inevitable,  therefore,  that  this  constant  bending  to  and  fro  should 
eventually  cause  a  series  of  cracks  to  appear  along  the  line  of  the  rivets 


BOILER    SAFETY   BUUvE/TlN.  23 

in  either  row,  which  are  evidently  the  lines  of  least  resistance,  and  that 
these  cracks  should  go  deeper  at  every  flexure  until  the  strength  of  the 
plate  is  finally  reduced  to  the  point  of  rupture.  It  is  one  of  the  mysteries 
of  the  phenomenon  that  these  cracks  invariably  manifest  themselves  first 
in  the  inner  surface  of  the  outer  lap,  and  never  in  the  outer  surface  of  the 
inner  lap. 

Thus  it  appears  that  opposition  to  the  lap-seam  boiler  construction, 
springs  not  from  any  contention  that  such  seams  are  unsafe  for  constant 
pressure,  but  from  the  evident  impossibility  of  maintaining  absolute 
uniformity  of  pressure  in  operation,  and  the  consequent  localization  at 
the  joint  of  the  breathing  movement  which  such  lack  of  uniformity 
entails,  as  well  as  from  the  fact  that  the  resultant  deterioration,  being 
hidden  between  the  lapped  ends  of  the  sheet,  precludes  all  possibility  of 
adequately  estimating  its  extent  without  actually  drawing  out  the  rivets 
and  taking  the  joint  apart. 

One  peculiar  fact  which  stands  out  quite  prominently  in  connection 
with  the  lap  seam  failures  of  the  past  is  that  wrought  iron  boilers  seem 
to  be  practically  immune  from  rupture  of  this  kind.  The  theory  has 
been  advanced  to  account  for  this  apparent  anomaly — for  anomalous  it 
seems,  since  it  is  the  popular  idea  that  the  use  of  steel  as  a  boiler 
material  reduces  the  liability  to  disaster  from  any  inherent  cause — 
is  that  the  laminated  structure  of  wrought  iron,  which,  on  general 
principles,  is  rather  an  objectionable  feature  than  otherwise,  acts  as  an 
obstacle  to  the  progress  of  the  deterioration,  inasmuch  as  a  crack  starting 
in  the  outer  stratum  of  metal  will  expend  itself  in  getting  through  that 
stratum,  so  that  an  entirely  new  crack  must  be  started  in  the  next  layer, 
and  thus  the  impairment  of  the  joint  is  arrested  and  delayed  from  time  to 
time,  but  is  never  entirely  overcome.  Steel,  on  account  of  its  homo- 
geneous texture,  is  deprived  of  this  advantage. 

However,  it  may  be  accepted  as  a  foregone  conclusion  deducible  from 
the  essential  character  of  this  latent  imperfection  in  longitudinal  lap 
seams,  that  any  boiler  having  such  seams,  whether  it  be  built  of  wrought 
iron  or  of  steel,  if  continued  in  service  long  enough,  and  spared  the 
ravages  of  corrosion  and  other  sources  of  wear  and  tear,  will  eventually 
go  to  pieces  by  rupture  of  those  seams  as  herein  described. 


APPLICATION  OF  INSIDE  WELT  STRAP  TO  OLD  LAP-SEAM 

BOILERS. 

By  R.  L.  HEMINGWAY,  Chief  Boiler  Inspector. 

There  is  probably  not  one  of  us  that  has  not  had  carefully  instilled  into 
him  the  value  of  economy  in  all  things,  and  while  it  is  perfectly  true 
that  economy  is  the  foundation  of  all  business,  it  does  seem  that  this 
trait  can  be  overdone,  at  least  in  so  far  as  it  applies  to  the  use  of  steam 
boilers.  Apparently,  too  strict  economy  was  the  object  of  many  con- 
cerns that  put  boilers  in  California  in  years  gone  by,  for  they  demanded 
and  obtained  cheap  boilers. 

In  order  to  obtain  a  cheap  boiler,  one  of  the  first  economies  that  the 
manufacturer  makes  is  in  the  thickness  of  plate  used  in  its  construction, 
at  the  expense  of  the  factor  of  safety.  Another  saving  is  accomplished 


24  BOILER   SAFETY   BULLETIN. 

by  adopting  the  lap-seam  construction  for  the  longitudinal  joints  of  the 
boilers. 

When  the  Boiler  Safety  Orders  became  effective  in  California  on 
January  I,  1917,  there  were  a  few  instances  in  which  the  pressures  on 
boilers  had  to  be  reduced,  owing  to  the  factor  of  safety  that  had  to  be 
applied,  on  account  of  the  age  of  the  boilers.  This  condition  will  recur 
year  after  year  as  age  accumulates  on  these  lap-seam  boilers.  Some 
owners,  rather  than  discard  their  old  equipment,  on  which  the  rules 
correctly  require  the  working  pressures  to  be  reduced  on  account  of  age, 
have  endeavored  to  find  some  means  of  extending  the  useful  life  of  their 
old  boilers,  which  still  bear  the  earmarks  of  being  good,  at  least  on  the 
surface.  In  doing  this  they  have  hit  upon  the  old  expedient  of 
strengthening  ordinary  double-riveted  lap-seam  joints  by  the  application 
of  what  is  sometimes  called  the  inside  welt-strap  joint,  or  the  locomotive 
joint.  The  latter  name  conies  from  the  not  infrequent  use  of  this  type 
of  joint  in  locomotive  boilers.  The  joint  itself  consists  of  an  ordinary 
double-riveted  lap-joint,  provided  with  an  inside  cover-plate,  which  is 
jogged  so  that  it  conforms  to  the  curvature  of  the  shell  on  both  sides  of 
the  lap-joint.  In  addition  to  the  rivets  in  the  double-riveted  lap-joint, 
there  is  also  an  outer  row  provided  on  each  side,  having  twice  the  pitch 
of  the  rivets  in  the  inner  rows.  This  will  be  more  readily  understood 
by  reference  to  figure  one. 


Fig.L 


Sectional  and  plan  view  of  lap  joint  with  inside  strap  applied. 

There  is  nothing  new  about  this  type  of  joint,  as  it  has  been  known 
and  used  for  many  years,  although  it  has  never  come  into  great  popularity, 
owing  to  the  fact  that  it  is  a  mere  subterfuge.  In  other  words,  while  the 
application  of  an  inside  welt  may  increase  the  efficiency  of  the  joint,  the 
joint  itself  still  remains  a  lap-joint,  and  as  such  it  may  be  regarded  as 
still  subject  to  the  development  of  the  hidden  cracks  and  to  fatigue  of 


SA^TY   BUL^TIN.  25 

the  metal  through  constant  flexure,  owing  to  the  breathing  action  of  the 
boiler  shell. 

About  1887  some  very  exhaustive  tests  were  made  on  this  welt-strap 
type  of  joint  at  the  Watertown  Arsenal  in  New  York,  in  order  to  deter- 
mine if  possible  just  what  increase  in  efficiency  this  type  of  joint  would 
furnish.  The  Government  engineers,  in  preparing  for  the  test,  chose  the 
very  best  possible  material  available  at  that  time,  the  utmost  care  being 
taken  in  the  preparation  of  the  joints  for  the  test.  In  addition  to  careful 
selection  of  material,  the  workmanship  in  the  riveting  was  performed 
under  the  very  best  possible  conditions.  Notwithstanding  these  facts, 
the  record  of  these  tests  shows  that  the  average  increase  in  efficiency  did 
not  amount  to  more  than  seven  and  one-half  per  cent  above  the  efficiency 
of  the  ordinary  double-riveted  lap-joint  to  which  no  cover  plate  was 
applied. 

This,  then,  is  the  expedient  to  which  quite  a  number  of  California 
boiler  owners  and  operators  have  recently  resorted  in  order  to  restore 
the  working  pressures  to  or  maintain  working  pressures  at  a  point  where 
they  can  still  continue  to  operate  their  plants.  The  probabilities  are  that 
if  this  type  of  joint  were  used  in  the  original  construction  of  the  boiler, 
there  would  be  considerably  less  objection  to  it  than  now  arises  in  apply- 
ing it  to  boilers  that  have  already  seen  some  years  of  service. 

It  will  be  readily  understood  that  one  can  not  remove  the  rivets  from 
a  longitudinal  lap-seam  without  seriously  affecting  the  strength  of  the 
joint  when  other  rivets  are  driven.  Then,  again,  it  is  entirely  problem- 
atical whether  even  the  closest  examination  of  the  insides  of  a  lap-joint 
would  reveal  the  infinitesimally  fine  cracks  which  may  be  present  in  the 
material  and  which,  although  so  fine,  are  still  a  pregnant  source  of 
danger. 

To  summarize,  the  locomotive,  or  inside  welt-strap  joint  is  no  better 
than  a  lap-seam,  beyond  the  fact  that  it  is  capable  of  a  theoretically 
higher  efficiency  than  is  the  ordinary  double-riveted  lap-joint.  It  is 
extremely  doubtful  whether  this  increase  in  efficiency  does  not  constitute 
an  increase  in  the  hazard  by  reason  of  the  fact  that  higher  pressures  are 
obtained  through  its  use. 

So  far  as  known  there  is  no  law  in  any  state  which  prohibits  the  use 
of  this  type  of  joint  and  probably  there  is  no  state  in  which  its  use  has 
attained  anything  like  the  prevalence  that  it  now  seems  to  be  gaining  in 
California. 

Lacking  precedent  for  prohibition  of  its  use,  this  type  of  joint  will  be 
accepted  on  conditions  to  be  determined  by  the  Industrial  Accident  Com- 
mission after  the  Boiler  Safety  Orders  revisions  committee  shall  have 
submitted  its  recommendations  to  the  Commission.  Under  no  consider- 
ation can  the  welt-strap  type  joint  be  recommended  from  an  engineering 
standpoint,  from  the  sandpoint  of  safety,  or  yet  from  the  standpoint  of 
economy.  It  may  be  trite  to  add  at  this  time,  but  it  is  no  less  true,  that 
safety  and  economy  are  inseparable  in  the  long  run. 


26  BOII^R   SAFETY   BUU,£TIN. 

THE  SINGLE-SHEET  LAP-SEAM  BOILER. 

By  J.  P.  MORRISON,  Chief  Inspector,  Hartford  Steam  Boiler  Insurance  and  Inspection 

Company. 

[Reprinted,  by  permission,  from  April  26,  1921,  issue  of  Power*.] 

The  single-sheet  lap-seam  boiler,  so  destructive  of  life  and 
property,  must  go.  An  analysis  of  its  weaknesses  is  evidenced 
by  numerous  explosions.  It  does  not  possess  a  sufficient  mar- 
gin of  safety,  is  made  of  questionable  material,  is  subject  to 
injuries  during  the  process  of  fabrication,  is  impossible  of 
thorough  inspection,  and  in  operation  is  stressed  beyond  the 
safe  limit  by  temperature  difference,  by  lack  of  girth-seam 
support  and  by  the  unequal  distribution  of  the  weight  of  the 
boiler,  contents  and  connections. 

It  is  probable  that  no  question  of  machine  design  has  received  more 
careful  and  intelligent  consideration  than  has  the  design  of  the  shell 
seams  of  steam  boilers.  Fairbairn's  tests  were  conducted  in  1838.  W. 
Bertram  conducted  tests  at  the  Woolwich  Dock  Yards  in  1860.  D.  K. 
Clark  discussed  riveted  seams  in  1877.  A  lap-seam  crack  was  reported 
in  The  Locomotive,  issued  in  April,  1880,  while  that  publication  dealt  at 
considerable  length  with  the  stresses  occurring  in  lap  seams.  On  April 
17,  1891,  J.  M.  Allen,  who  was  then  president  of  the  Hartford  Steam 
Boiler  Inspection  and  Insurance  Company,  delivered  a  lecture  at  Sibley 
College,  in  which  he  gave  a  complete  diagnosis  of  the  various  joints  then 
in  use,  having  particular  reference  to  the  triple-riveted  butt-strap  joint. 
This  lecture  was  published  and  widely  distributed,  and  the  principles  set 
forth  are  those  upon  which  the  calculations  of  riveted  joints,  encountered 
in  modern  practice,  are  based.  In  the  early  days  of  steel-plate  manu- 
facture the  product  was  confined  to  sheets  of  small  dimensions.  As  a 
consequence  the  boilers  built  in  those  days  were  composed  of  a  number 
of  courses,  and  each  course,  if  the  boiler  was  unusually  large,  would  be 
made  up  of  several  sheets.  It  was  not  uncommon  to  encounter  a  boiler 
14  feet  in  length  and  48  inches  in  diameter  made  up  of  seven  courses 
formed  of  four  sheets  each.  But  as  the  steel  makers  became  able  to 
produce  larger  plates,  boilers  were  constructed  of  a  lesser  number  of 
courses,  each  composed  of  fewer  sheets.  This  appeared  to  be  of  con- 
siderable advantage  in  many  ways,  and  when  it  became  possible  to 
produce  plates  of  such  size  that  only  two  were  needed  to  form  the  shell 
plates  of  a  boiler,  they  found  a  ready  market.  With  the  development  in 
steel  manufacturing  the  importance  of  the  physical  and  chemical 
properties  of  the  boiler  plates  was  recognized,  particular  emphasis  being- 
placed  on  the  advantages  of  great  ductility  even  when  obtained  at  a  loss 
in  ultimate  tensile  strength.  Laminations  found  in  steel  plate  had  elicited 
some  criticism,  and  there  was  a  loud  protest  at  the  practice  of  some  steel 
makers  of  shipping  unbranded  plates,  for  the  boilermakers  were  begin- 
ning to  realize  the  necessity  of  having  the  steel  maker's  brand  appear  on 
each  sheet  of  the  finished  boiler.  Boiler  plates  manufactured  by  both 
the  open-hearth  and  Bessemer  processes  were  used,  and  it  was  under- 
stood that  the  quality  of  the  boiler  plate  depended  more  upon  the  grade 
of  raw  materials  than  upon  the  particular  process. 

*Cuts  to  illustrate  this  reprint  were  loaned  by  the  editor  of  Power,  10th  Avenue  at  36th  St., 
New  York. 


SAFETY   BULLETIN.  27 

Difficulty  that  had  been  experienced  by  reason  of  girth-seam  leakage, 
fire  cracks  and  mud  burns,  all  attributed  to  the  sediment  within  the 
boiler  accumulating  against  the  girth-seam  laps,  gave  added  attraction 
to  the  idea  of  rolling  one  sheet-  to  form  the  bottom  half  of  the  boiler. 
The  upper  half  continued  in  some  cases  to  be  constructed  of  two  or  three 
plates,  while  in  other  cases  one  large  plate  only  was  used.  This  form' of 
construction  necessitated  the  use  of  a  longitudinal  seam  on  each  side 
of  the  boiler  extending  from  head  to  head,  and,  was  confined  to  shops 
having  plate-bending  rolls  of  sufficient  length  to  pass  a  i6-ft.  or  i8-ft. 
sheet  between  housings. 

It  is  worthy  of  note  that  this  construction  was  criticised  twenty-five 
or  more  years  ago,  and  subsequent  developments  have  proved  the  cor- 
rectness of  those  who,  while  without  sufficient  facts  at  hand  to  justify 
outright  condemnation  of  the  single-sheet  boiler,  brought  its  weaknesses 
to  public  attention  and  withheld  approval,  citing  the  explosion  of  one 
boiler  due  to  the  single  bottom  sheet  construction,  and  which  resulted  in 
the  loss  of  two  lives  and  an  estimated  property  damage  of  $5,000.  Those 
unacquainted  with  shop  practice  of  the  older  days  will  hardly  realize  the 
possible  damage  done  to  a  sheet  during  the  process  of  fabrication  of  the 
boiler.  The  rivet  holes  were  punched  full  size,  except  where  special 
requirements  were  to  be  met,  so  the  mill  cracks  started  by  the  punching 
process  were  not  removed.  Few  of  the  shops  were  equipped  with  a 
press  to  shape  the  ends  of  the  sheet  to  the  proper  curvature.  The  work 
was  done  by  placing  the  sheet  over  a  rail  or  one  of  the  bending  rolls  and 
sledging  the  edges,  often  stressing  the  questionable  material  beyond  its 
elastic  limit  along  the  line  of  rivet  holes  in  the  second  row,  where  the 
sheet  had  already  been  weakened  by  the  reduction  of  the  metal  and  by 
mill  cracks,  due  to  punching  the  rivet  holes.  To  this  were  added  the 
stresses  set  up  when  the  poorly  fitting  joint  was  bolted  up  and  later 
riveted.  Usually,  the  joint  was  then  sledged  into  shape  for  calking. 

Fig.  i  indicates  the  change  in  shape  of  the  ends  of  a  plate  when 
being  formed  over  the  roll  by  the  use  of  the  sledge.  Fig.  2  illustrates 
the  condition  of  the  ends  of  the  plate,  after  the  rest  of  the  plate  has  been 
rolled  to  the  proper  curvature.  The  ends,  having  been  shaped  by  blows 
of  the  sledge,  do  not  conform  to  the  true  curvature.  That  was  also  the 
era  of  the  drift  pin,  when  an  unfair  hole  could  be  made  fair,  adding  more 
stresses  to  the  sheet  along  the  line  of  rivet  holes. 

Even  then  the  trend  of  the  times  was  toward  boilers  of  larger 
diameter.  Since  the  size  of  the  plates  obtainable  would  not  permit  locat- 
ing the  head-to-head  seams  above  the  horizontal  diameter,  the  seams  of 
such  a  boiler  were  exposed  to  furnace  temperatures,  in  addition  to  the 
stresses  due  to  difference  in  temperature  of  the  upper  and  the  lower 
section  of  the  boiler,  the  former  being  exposed  to  the  atmosphere,  while 
the  latter  was  subjected  to  furnace  heat  as  indicated  in  Fig.  4.  The 
intensity  of  these  stresses  would  vary  considerably,  but  one  authority  has 
reported  them  as  amounting  to  approximately  6,000  Ib.  per  square  inch. 


28  BOILER    SAFETY   BULLETIN. 

The  never-ending  effort  of  the  contained  pressure  to  perform  the 
impossible  feat  of  rounding  out  the  irregular  surface  existing  at  the  lap 
seams  produces  the  lap-seam  crack,  for  which  this  joint  is  notorious.  In 
Fig.  3,  x  and  z  indicate  the  development  of  such  a  crack,  while  Fig.  5 


FI63 

Fig.  1.     Forming  end  of  plate  over  roll. 

Fig.  2.     Ends  of  plate  to  be  sledged  to  shape. 

Fig.  3.     Lap  seam  stressed  to  failure. 

shows  a  crack  that  developed  in  a  plate  in  service.  Furthermore,  this 
lack  of  symmetry  renders  the  plate  along  the  line  of  greatest  stresses 
susceptible  to  corrosive  action,  which  would  be  intensified  where  there 
were  three  pairs  of  supporting  brackets,  as  was  the  case  with  large 
boilers;  and  the  settling  of  the  furnace  walls  at  the  front  or  rear  trans- 
ferred the  load,  amounting  to  one-half  the  weight  of  the  boiler  and 
contents,  onto  the  center  bracket. 

The  strengthening  effect  of  the  girth  seam  has  been  the  subject  of 
considerable  discussion.  It  is  in  principle  quite  the  same  as  applying  a 
hoop  to  the  circumference  of  the  boiler.  This  is  evidenced  in  a  number 
of  instances  when,  upon  the  vessel  being  stressed  beyond  the  elastic  limit, 
the  increase  in  circumference  did  not  even  extend  to  the  girth  seam, 
owing  to  the  hoop  effect  of  the  seam.  The  fact  that  the  explosion  of  a 
two-  or  three-course  boiler,  due  to  lap-seam  failure,  rarely  results  in  a 
rupture  extending  across  a  girth  seam  should  leave  no  need  of  further 
argument  in  favor  of  a  construction  embodying  girth  seams. 

Before  the  double-strapped  butt  joint  was  universally  adopted,  a  large 
number  of  lap-seam  boilers,  many  of  them  of  the  single-sheet  variety, 
were  placed  in  operation.  The  majority  of  these  boilers  were  intended 
for  loo  Ib.  pressure,  using  a  factor  of  safety  of  4.  This  factor  has 
been  generally  recognized  as  inadequate  even  for  boilers  of  superior 
construction,  and  could  not  be  expected  to  be  continued  as  satisfactory 
for  lap-seam  boilers  after  a  few  years  of  service  and  abuse.  ( Italics  ours.) 

After  considering  the  various  factors  having  a  direct  influence  on  the 
safety  of  single-sheet  boilers,  it  does  not  appear  strange  there  have  been 
so  many  violent  explosions,  with  the  loss  of  numerous  lives  and  property 
damage  approximating  a  million  dollars  in  value.  The  facilities  for 


BOILER   SAFETY 

-^ 

investigating  boiler  explosions  were  probably  not  in  keeping  with  the 
general  industrial  activities,  but  in  the  early  days,  when  80  to  100  Ib. 
pressure  was  considered  high,  each  explosion  was  more  or  less  shrouded 
in  mystery,  and  the  theories  advanced  as  to  the  cause  were  about  as 
intricate  and  vague  as  could  be  imagined.  The  presence  of  a  super-gas, 
the  spheroidal  state  of  the  water,  the  geyser  action  of  the  water,  super- 
heated water,  low  water  or  no  water,  inflammable  steam  and  the  presence 
of  a  vacuum  were  theories,  each  of  which  had  its  following.  The  cause 
of  the  difficulty,  the  single-sheet  lap-seam  crack,  was  generally  over- 
looked by  investigators  seeking  to  establish  the  correctness  of  their  pet 
theory  as  to  the  force,  or  phenomena  causing  the  destruction.  A  few 
engineers  realized  the  influence  of  manufacture  on  boiler  safety.  Zera 
Colburn  is  quoted  as  stating  in  1880,  "All  our  knowledge  of  boiler 
explosions  goes  to  show  that  in  the  majority  of  cases  the  actual  explosion 
results  from  some  defect,  either  original  or  produced,  and  either  visible 
or  concealed,  in  the  material,  workmanship  or  construction  of  the  boiler." 
There  is  no  complete  list  of  explosions  of  single-sheet  boilers  nor  of 
the  number  that  have  been  found  to  be  unsafe  and  discarded  from  service, 
but  the  record  available  is  sufficient  to  indicate  clearly  the  unusual  hazard 
attending  the  operation  of  boilers  of  that  description.  The  condemnation 
of  a  boiler  having  a  seam  crack  14  feet  in  length  was  recorded  in  1894, 


Fig.  4.     Seams  of  single-sheet  boiler  inaccessible  and  exposed  to  furnace  heat. 


3O  BOILER   SAFETY   BULLETIN. 

and  on  February  i,  1895,  a  boiler  66  inches  in  diameter  by  16  feet  long, 
containing  54  four-inch  tubes,  and  constructed  of  steel  plates  %  inches 
thick,  forming  a  single  course  of  the  bottom  of  the  boiler  and  three 
courses  of  the  top,  exploded  in  an  electric  light  plant  with  disastrous 
results.  One  man  is  reported  to  have  been  killed,  three  others  seriously 
injured,  and  the  power  plant  totally  wrecked.  The  line  of  failure  fol- 
lowed the  seam  from  the  head  two-thirds  of  the  length  of  the  boiler, 
from  which  point  separation  occurred,  the  girth  seam  being  followed 
across  the  top  of  the  boiler  by  one  branch  of  the  crack,  and  the  other 
extending  through  the  solid  plate  downward  toward  the  rear.  The 
boiler  had  three  pairs  of  supporting  lugs,  and  conditions  indicated  that 
the  initial  failure  occurred  under  the  middle  lug. 

The  Rochester,  N.  Y.,  Brewery  explosion  followed  in  1889,  and 
caused  the  death  of  one  man,  as  well  as  property  damage  estimated  at 
$25,000.  On  November  26,  1901,  a  disastrous  explosion  of  a  66-inch  by 


Fig.  5.     A  lap-joint  crack. 

1 6-foot  boiler  at  the  plant  of  the  Penberthy  Injector  Works,  Detroit, 
Mich.,  demolished  a  three-story  brick  building  and  cost  the  lives  of 
thirty  and  seriously  injured  thirty-five  others.  The  total  property 
damage  was  estimated  at  $100,000.  This  boiler  had  seen  but  six  or  seven 
years  of  service  and  was  understood  to  be  in  good  condition.  The  line  of 
failure  followed  the  longitudinal  seam  on  one  side  of  the  shell,  sub- 
stantially in  a  straight  line  from  one  head  to  the  other. 

Of  a  single-sheet  boiler  the  next  violent  explosion  of  which  record  is 
available,  occurred  at  the  plant  of  the  American  Tin  Plate  Company, 
Canton,  Ohio,  on  May  n,  1910,  and  was  reviewed  in  the  issue  of  Power 
of  May  31,  of  that  year.  Then  followed  the  Midvale,  Ohio,  explosion 
and  the  Shelton,  Conn.,  explosion  in  1911;  the  Pleasant  Valley,  Conn., 
explosion  in  1915 ;  the  Athol,  Md.,  explosion  in  1916,  and  the  Cross  Run, 
Pa.,  explosion  in  1917;  all  bearing  the  earmarks  of  lap-seam  defects  and 
occurring  to  single-sheet  boilers,  taking  the  usual  toll  in  life  and  damaged 
property. 

While  the  Fargo,  Tex.,  explosion,  occurring  on  October  i,  1914,  was 
caused  by  a  lap-joint  failure  of  a  single-sheet  boiler,  it  differed  materially 
from  some  of  those  previously  mentioned,  inasmuch  as  the  boiler  had 
been  carefully  examined  by  an  expert  inspector  and  pronounced  unsafe 


SAFETY 


to  operate,  his  opinion  being  based  on  the  corrosion  which  had  attacked 
the  longitudinal  seam.  These  seams  were  not  visible  on  account  of 
their  location  below  the  upper  tubes,  but  after  cleaning  those  parts  as 
thoroughly  as  possible,  the  inspector  determined  by  his  finger  tips  that 
there  had  been  so  much  reduction  in  thickness  that  there  was  not  suf- 
ficient strength  to  withstand  the  pressure.  However,  the  owner  placed 
the  boiler  in  operation,  and  the  second  day  thereafter  it  exploded,  killing 
two  men,  injuring  two  others  and  wrecking  the  plant.  Investigation 
developed  the  fact  that  the  rupture  had  occurred  in  the  outer  sheet  of 
the  lap,  that  sheet  forming  the  bottom  half  of  the  boiler,  as  is  common 
with  single-sheet  construction,  and  followed  a  line  parallel  to  the  edge 
of  the  inner  lap,  extending  from  head  to  head  through  metal  which, 
owing  to  corrosion,  did  not  average  %  inch  in  thickness. 

The  accompanying  photographs,  Figs.  6  to  8,  illustrate  the  damage 
done  by  the  explosion  of  a  single-sheet  boiler,  which  resulted  in  the 
death  of  two  workmen,  and  serious  injury  of  two  others,  and  the  total 


Fig.  6.     Result  from  the  explosion  of  a  single-sheet  boiler. 

destruction  of  the  plant.  Fig.  6  gives  a  good  idea  of  the  general 
damage  to  the  plant,  and  Fig.  7  is  a  close-up  view  of  the  boiler  tubes 
and  head.  The  boiler  was  said  to  have  been  about  24  years  old,  and 
its  builder  was  unknown,  as  it  had  been  used  elsewhere  and  had  changed 
owners  a  number  of  times.  So  far  as  couM  be  learned,  the  boiler 
never  had  been  subjected  to  an  examination  by  "anyone  qualified  to  pass 
judgment  in  such  matters.  The  double-riveted  lap  seams  extended  from 
the  front  head  to  the  rear  head  on  each  side  of  the  boiler.  The  means  of 
support  consisted  of  three  pairs  of  castiron  brackets  resting  on  the 
furnace  walls,  one  being  between  the  dome  and  longitudinal  seams,  on 
either  side  of  the  boiler.  The  pressure  carried  at  the  time  of  the  explo- 
sion was  loo  lb.,  and  it  was  probable  the  builder  sold  the  boiler  when  new 
with  the  customary  guarantee  of  that  pressure,  which  would  be  permitted 
by  a  factor  of  safety  of  4. 

Some  time  previous  to  the  accident  leakage  was  observed  at  the 
longitudinal  seam  under  one  of  the  center  support  brackets.  A  boiler- 
maker  of  questionable  ability  and  experience  patched  the  seam  as 


32  BOILER   SAFETY   BULLETIN. 

indicated  by  the  arrow  in  Fig.  8,  apparently  without  giving  thought  to 
the  cause  of  the  difficulty,  but  riveting  the  patch  at  the  boiler  seam,  and 
using  patch  bolts  for  securing  the  new  seam.  The  boiler  was  continued 
in  operation  without  further  trouble  until  about  a  week  before  the 
explosion,  when  seam  leakage  was  again  observed.  The  mill  superin- 
tendent and  an  employee  are  said  to  have  drilled  and  threaded  for 
•"54-inch  capscrews,  four  holes  along  the  seam  where  leakage  had 
appeared.  A  soft  patch  consisting  of  a  sheet  of  plow  steel  and  a  thin 
sheet  of  lead  was  secured  to  the  boiler  by  means  of  capscrews  and  nuts, 
and  the  boiler  was  again  placed  in  service. 

The  failure  occurred  in  the  sheet  forming  the  lower  part  of  the  boiler, 
on  a  line  coinciding  with  the  edge  of  the  inner  lap,  just  about  the  same 
location  as  in  the  failure  of  the  Fargo,  Tex.,  boiler,  and  did  not  follow 
nor  enter  the  rivet  holes.  It  extended  the  entire  length  of  the  seam,  as  is 
customary  with  violent  failure  of  this  kind.  The  rivets  in  the  head 


Fig.  7.     Close-up  view  of  boiler  tubes  and  head. 

seams  either  sheared  at  the  junction  of  the  plates  or  the  rivet  heads 
pulled  off,  as  none  of  the  rivet  holes  were  destroyed,  although  some  of 
them  were  found  to  be  considerably  elongated. 

After  an  accident,  where  there  are  so  many  possible  causes,  it  is  difficult 
to  define  responsibility.  In  this  case  the  center  bracket  above  the  point 
where  the  initial  leakage  and  crack  developed,  most  likely  supported  the 
entire  weight  of  that  side  of  the  boiler,  which,  as  has  been  outlined, 
would  follow  from  the  settling  of  the  furnace  at  the  front  or  back 
bracket,  and  would  clearly  justify  the  modern  requirements  which  pro- 
vide for  four-point  suspension  only.  The  factor  of  safety  was  not 
one-half  as  great  as  considered  necessary  by  good  authorities  for  boilers 
of  such  great  age  and  design,  and  had  a  proper  factor  of  safety  been 
maintained,  the  explosion  would  not  have  occurred,  as  the  pressure  per- 
mitted then  would  not  have  been  sufficient  to  operate  the  plant,  and  the 
boiler  would  have  been  scrapped. 

Had  the  service  of  the  boiler  been  limited  to  ten  years,  as  has  been 
advocated  for  the  lap-seam  boiler,  its  use  would  have  been  abandoned 


33 

years  before.  The  owner  no  doubt  would  have  experienced  some  financial 
loss,  but  nothing  compared  to  the  loss  resulting  from  the  explosion.  Had 
the  boilermaker  who  patched  the  boiler  been  acquainted  with  develop- 
ments of  recent  years,  so  far  as  boiler  design  and  safety  are  concerned, 
and  the  rules  which  prohibit  repairing  a  boiler  in  which  a  lap-seam 
crack  has  developed,  or  had  the  mill  superintendent  realized  the  clear  dan- 
ger warnings  and  discontinued  the  boiler  from  service  until  the  advice  of 
competent  persons  could  be  obtained,  there  would  have  been  no  explosion. 
This  accident  emphasizes  the  difficulty  of  obtaining  proper  coopera- 
tion of  boiler  owners  in  enforcing  reasonable  rules  and  regulations,  as 
the  boiler  was  being  operated  without  a  certificate  from  the  state 
authorities,  who  had  no  knowledge  of  its  existence,  and  it  is  doubtful  if 
the  owner  and  those  in  charge  of  its  operation  knew  that  the  boiler  dif- 
fered in  any  material  way  from  new  boilers  of  modern  design. 

Fortunately,  the  installation  of  new  boilers  of  this  description  is 
prohibited  in  many  states  and  cities,  so  its  manufacture  practically  has 
been  abandoned,  but  there  are  a  great  number  in  operation,  and  the  next 
few  years  may  witness  an  increasing  number  of  failures,  as  the  defects, 
undoubtedly  existing,  develop  until  rupture  takes  place.  An  increase  in 
the  factor  of  safety  will  result  in  a  reduction  of  pressure ;  this  may  cause 
the  removal  of  the  boiler  from  its  present  place  of  operation,  to  be  dis- 
posed of,  if  there  are  no  restrictions,  through  dealers  in  second-hand 
boilers,  only  to  be  placed  again  in  service,  to  the  jeopardy  of  someone's 
life  and  property. 

In  discussing  the  Cross  Run,  Pa.,  explosion,  The  Locomotive,  in  the 
July,  1917,  issue,  asserts:  "The  lap-seam  boiler  has  been  a  fruitful 


Fig.  8.     Shell  plates  blown  free  of  the  ends  and  tubes. 

source  of  steam-boiler  accidents  in  this  country,  and  of  lap-seam  boilers 
perhaps  no  class  has  been  more  subject  to  disaster  than  those  made  in  a 
single  course  with  two  sheets,  one  above  and  one  below."  It  is  evident 
that  the  single-sheet  boiler  "has  been  weighed  in  the  balance  and  found 
wanting."  It  has  sustained  injuries  during  the.  process  of  fabrication, 
is  impossible  of  thorough  inspection,  has  been  stressed  beyond  its  safe 
limit  by  temperature  difference,  by  continual  flexure  due  to  nonconformity 
to  a  true  circle,  by  lack  of  girth-seam  support,  and  by  the  unequal  dis- 
tribution of  the  weight  of  the  boiler,  contents  and  connections. 


34  BOIIvER   SAFETY   BULLETIN. 

Shall  those  boilers  now  in  use  be  continued  in  service,  to  change 
owners  and  operating  conditions  at  will,  until  each  gives  positive  and 
direct  evidence  of  its  worthlessness  by  exploding,  with  the  aggregate  loss 
of  another  hundred  of  lives,  and  of  another  million-dollar  property 
damage?  Or  shall  the  rule  against  habitual  criminals  be  invoked,  and 
each  boiler  of  that  type  sentenced  permanently  to  the  scrap  yard,  where 
it  will  have  no  further  opportunity  to  destroy,  just  as  the  police  character, 
in  whom  the  bad  outweighs  the  good,  is  given  an  indeterminate  prison 
sentence,  so  he  can  do  no  more  injury  to  society?  If  those  financially 
responsible  for  the  continued  operation  of  single-sheet  boilers  could  be 
made  to  realize  that  immediately  preceding  each  lap-seam  boiler  accident 
the  owner  considered  his  boiler  perfectly  safe  to  operate ;  or  appreciated 
the  fact  that  under  certain  circumstances  any  person  might  be  the  victim, 
as  our  sidewalk  basement  boiler  rooms,  hotel  power  plants  and  depart- 
ment store  power  plants,  if  they  do  not  contain  unquestionably  safe 
equipment,  place  the  lives  of  all  in  jeopardy;  or  realized  that  defective 
boilers  endanger  the  lives  of  the  employees  to  whom  the  employer  owes 
the  moral  responsibility  of  furnishing  safe  tools — then  there  is  no  ques- 
tion that  the  verdict  would  be,  "The  single-sheet  boiler  must  go." 

CHANGING  OLD  LAP  SEAM  BOILERS  TO  BUTT  SEAM 
CONSTRUCTION.* 

Not  long  after  the  steam  boiler  came  into  general  use  in  America 
.considerable  discussion  was  aroused  with  respect  to  the  question  of 
limiting  the  life  of  a  boiler.  Numerous  instances  of  serious  accident, 
which  it  seemed  impossible  to  account  for,  had  impressed  many  with  the 


Fig.  1.     When  plates  are  rolled  to  a  cylindrical  form  there  is  a  tendency  for 
plate  edges  to  remain  flat  as  in  this  case. 

idea  that  a  boiler,  like  any  other  piece  of  apparatus,  was  subject  to 
deterioration  from  constant  use  and  that  therefore  it  would  be  best  to 
take  a  boiler  out  of  service  after  a  certain  period.  In  fact,  a  number  of 
concerns  followed  this  practice.  The  majority  of  boiler  users  and 

*From  The  Locomotive,  Hartford  Steam  Boiler  Inspection  and  Insurance  Company,  Hartford, 
Conn.  Cuts  to  illustrate  this  reprint  were  loaned  by  The  Boiler  Maker,  6  Fast  39th  St.,  New 
York. 


BOILER  SAFETY  BULLETIN.  35 

engineers,  however,  felt  then,  as  they  do  now,  that  rigid  inspection 
would  safeguard  their  boiler  plants  and  would  furthermore  be  of  greater 
service  in  the  interest  of  economy,  for  it  was  admitted  that  many  boilers 
had  served  for  twice  the  life  that,  by  some,  had  been  allowed  for  safety. 

The  plan  of  relying  on  inspection  for  a  forewarning  was  adopted  and 
served  well,  but  there  were  a  number  of  unaccountable  explosions  in 
boilers  of  relatively  short  life.  At  the  time,  the  majority  of  boilers  in 
use  were  constructed  with  a  longitudinal  lap  joint.  A  series  of  investi- 
gations was  conducted  to  study  the  stress  conditions  in  this  type  of  joint, 
and  it  was  found  that  the  construction,  both  from  its  fundamental  shape 
and  the  conditions  of  manufacture,  presented  a  most  dangerous  condition. 

In  The  Locomotive  for  April,  1905,  there  appeared  an  account  of  the 
disastrous  boiler  explosion  at  Brockton,  Mass.,  on  March  20,  1905,  and 
also  an  article  on  the  "Lap-joint  Crack,"  to  which  type  of  defect  the 
explosion  was  said  to  be  due.  For  the  sake  of  clearness  we  shall 
present  here  some  of  the  more  important  points  which  were  brought 
out  in  the  last-named  article. 

When  a  boiler  plate  is  rolled  to  a  cylindrical  form  the  edges  of  the 
plate,  in  passing  through  the  rolls,  are  not  gripped  as  effectively  as  is 
the  middle  of  the  plate,  so  that  the  ends  are  left  somewhat  flat.  The 
condition  produced  is  illustrated  in  Fig.  I.  This  necessitates  the  plates 
being  forced  together  at  the  edges,  and  this  produces  an  added  stress 
that  persists  unless  relieved  by  annealing.  In  addition  to  this,  the  plates, 
if  bent  after  punching,  will  bend  along  a  line  of  rivet  holes  as  shown  in 
Fig.  2  in  somewhat  exaggerated  form. 

The  elementary  lap  joint  is  illustrated  in  Fig.  3.  If  tension  is  applied 
as  indicated  in  Fig.  4,  the  plates,  in  an  attempt  to  aline  themselves 
with  the  load,  will  bend  along  a  line  running  under  the  outer  edge  of 
the  rivet  heads. 

The  combined  effect  of  all  these  conditions,  together  with  the  constant 
bending  of  these  joints  by  changes  of  pressure  when  in  use,  is  to  impose 
excessive  stresses  in  the  surface  of  the  boiler  plate  along  the  line  just 
mentioned.  This  has  produced,  in  many  boilers,  a  crack  which  starts 
always  from  the  inside  or  covered  surface  of  the  inside  or  the  outside 
plate  of  the  joint  as  indicated  at  A  and  B  in  Fig.  4.  This  crack  may 
eventually  work  its  way  through  the  plate  until  it  shows  itself  by  leakage. 
But  in  many  cases  it  may  develop  for  some  distance  along  the  joint  and 
yet  remain  absolutely  invisible.  Eventually  the  weakness  may  develop 
to  the  point  of  complete  failure  and  a  disastrous  explosion. 

Inspection  is  generally  accepted  as  being  safe  for  the  determination  of 
the  fitness  of  a  boiler  for  use.  The  lap  seam  crack,  however,  is  invisible 
to  all  methods  of  inspection,  except  cutting  out  the  rivets  and  separating 
the  plates.  Recognizing  the  insidious  danger  presented  in  the  lap  joint 
for  longitudinal  seams  in  boilers,  the  Boiler  Code  Committee  of  the 
American  Society  of  Mechanical  Engineers  formulated  the  following 
regulation  (par.  380,  A.S.M.E.  Boiler  Code,  edition  1918)  : 

"The  age  limit  of  a  horizontal  return  tubular  boiler  having  a 
longitudinal  lap  joint  and  carrying  over  50  pounds  pressure  shall  be  20 
years,  except  that  no  lap  joint  boiler  shall  be  discontinued  from  service 
solely  on  account  of  age  until  5  years  after  these  rules  become  effective." 

Some  boiler  owners  may  be  of  the  opinion  that  the  longitudinal  lap 
seams  of  boilers  of  this  type  can  be  changed  to  butt  strap  construction 


BOILER    SAFETY   BULLETIN. 


and  the  boilers  kept  in  service  after  the  time  limit.  This  change  of 
design  and  construction  is  not  approved,  however,  by  those  thoroughly 
familiar  with  steam  boilers,  for,  although  butt  straps  and  more  rivets 
may  be  added,  the  material  along  the  line  of  the  joint,  which  was  abused 
and  tortured  by  the  forming  of  the  lap  joint  and  fatigued  by  the  years  of 
service  which  subjected  it  to  the  expansion  and  contraction  brought 
about  by  the  many  changes  of  temperature  and  pressure,  would  be  further 
abused  on  the  portion  of  the  original  construction  left  after  cutting  off 
one  side  of  the  lap  joint  and  forcing  the  edges  of  the  plate  into  line  to 
form  a  butt  joint. 

Assuming  that  a  double  riveted  lap  joint  has  been  changed  to  a  triple 
riveted  butt  construction,  the  joint,  after  placing  the  butt  straps  and 
riveting,  would  appear  as  shown  in  Fig.  5  with  the  rivet  holes  of  the 
original  lap  joint  at  B  and  the  new  holes  at  C.  If  a  defect  existed  in  the 


Fig.  2.     If  bent  after  punching,  plates  will  bend  along  a  line  of  rivet  holes. 

plate  as  shown  at  A  the  joint  would  be  very  faulty.  Assuming  the 
original  joint  as  having  the  rivet  holes  spaced  3^  inches  and  the 
additional  holes  spaced  6y2  inches,  if  the  plate  material  were  defective 
or  contained  a  lap  crack  as  shown,  the  failure  of  the  joint  would  require 
only  the  shearing  of  the  rivets  in  long  pitch,  or  6^/2  inches,  and  the 
failure  of  the  defective  plate. 


Fig.   3.     Elementary  lap  joint. 


Fig.  4.     Effect  of  tension  on  joint. 


It  might  be  argued  that  the  exposure  of  the  inside  of  the  lap  seam, 
when  the  change  to  a  butt  seam  is  made,  would  reveal  the  presence  of  a 
lap-seam  crack.  A  crack  of  this  nature  is,  however,  often  present  in  a 
boiler  of  this  construction  after  years  of  service,  although  it  may  not 
be  visible  to  the  naked  eye.  But  even  though  no  crack  exists  it  must  be 
remembered  that  boiler  plate,  like  any  other  material,  becomes  fatigued 
after  long  years  of  service,  and  for  this  reason,  after  it  has  been  under 
stress  for  many  years,  it  should  not  be  subjected  to  a  change  of  shape  and 
torture  of  the  material  in  an  endeavor  to  keep  the  boiler  in  service, 
especially  when  there  is  evidence  that  the  altered  structure  is  defective. 

The  age  limit  of  twenty  years  is  none  too  exacting,  as  will  be  evidenced 
by  an  explosion  resulting  from  a  lap  seam  crack  of  a  boiler  at  the 
Tallahoma  Lumber  Company  at  Mossville,  Miss.,  on  October  21,  1920. 


BOILER    SAFETY    BULLETIN. 


37 


This  boiler  was  less  than  five  years  old.  The  explosion  completely 
wrecked  the  plant,  killed  three  men  and  injured  four  others.  There  was 
no  negligence  on  the  part  of  the  operators  and  there  was  ample  proof 
that  the  accident  did  not  result  from  low  water  or  overheating.  On  the 
other  hand,  the  lap  seam  cracks  could  be  clearly  seen  in  the  boiler  plates 
after  the  disaster. 

Regulations  such  as  we  have  quoted  are  not  intended  to  be  arbitrary. 
Railroad  companies  determine  the  safe  load  capacity  for  each  of  their 
freight  cars,  and  if  they  discover  an  overloaded  car  they  refuse  to  trans- 


Fig.  5.     Double  riveted  lap  joint  changed  to  triple  riveted  butt  strap  type. 

port  it.  This  is  done  not  only  to  avoid  the  possibility  of  straining  and 
breaking  the  overloaded  car,  but  also  to  prevent  a  possible  wreck  which 
might  result  in  loss  of  life,  property  damage  and  delay.  In  a  like  man- 
ner the  Boiler  Code  Committee  requests  that  steam  boilers  and  pressure 
vessels  be  designed  and  constructed  for  a  safe  working  pressure  and 
that  they  be  not  subjected  to  overloads.  The  rule  quoted  above  is  sane 
and  economic  because  it  is  intended  for  the  protection  of  life,  limb  and 
property.  So  also  should  be  regarded  the  action  of  the  boiler  inspector 
condemning  any  construction  regarded  as  unsafe. 


3<5  BOILER    SAFETY   BULLETIN. 

LAP  SEAM  CRACK  CAUSES  BOILER  FAILURE  IN  PLANING  MILL.* 

[Reprinted,  by  permission,  from  April,   1921,  issue  of  The  Boiler  Maker.] 

Many  of  the  details  of  boiler  making,  and  in  that  term  we,  of  course, 
include  boiler  repairing,  have  found  no  place  in  written  language  but 
may  be  said  to  be  traditional,  being  handed  down  from  the  journeyman 
to  the  apprentice,  by  word  of  mouth.  Other  details  may  be  said  to  be 
proprietary,  that  is,  some  workman  experiments  with  new  processes, 
until  he  becomes  acquainted  with  some  formerly  unknown  fact,  applicable 
to  the  trade,  of  which  he  immediately  takes  advantage,  with  satisfactory 
personal  results,  and  with  some  permanent  benefit  to  the  trade  in  general, 
when  the  detail  becomes  more  widely  known. 

The  good  workman  is  proud  of  the  results  of  his  efforts,  and  when 
trade-pride  ceases  to  exist,  whether  he  be  manufacturer  or  workman,  he 
may  no  longer  be  depended  upon,  and  sooner  or  later  his  work  will 
become  outclassed.  In  order  to  obtain  satisfactory  results,  a  complete 
understanding  of  the  trade  is  essential.  The  boiler  maker  doing  repair 
work  is  thrown  more  upon  his  own  resources  than  is  the  workman 
engaged  in  routine  shop  work.  When  on  new  construction,  the  foreman 
and  other  journeymen  are  usually  near  at  hand  for  advice  when  neces- 
sary. It  may  be  said,  however,  that  friendly  counsel  and  conferences  of 
a  trade  nature  are  far  too  uncommon. 

EXPERIENCE  REQUIRED  IN  REPAIR  WORK. 

At  any  rate,  when  a  call  for  outside  repair  work  is  received,  one  of  the 
most  capable  and  experienced  men  in  that  class  of  work  is,  or  should  be, 
sent  to  the  job,  for  it  is  impossible  to  determine  the  far  reaching  effects 


Fig.   1.     Result  of  boiler  explosion  in  planing  mill,  Antlers,  Okla. 

of  a  lapse  in  judgment,  when  outlining  the  repairs  to  be  made,  and  the 
manner  of  making  them.  The  owner  of  a  boiler  is  anxious  to  obtain 
the  greatest  possible  term  of  service,  consistent  with  safety,  and  is  often 

*Cuts  to  illustrate  this  reprint   were  loaned   by  the  publishers  of   The  Boiler  Maker,   6  East 
39th  St.,  New  York. 


BOILER   SAFETY   BULLETIN. 


39 


willing  to  spend  more  for  patches,  new  tubes,  or  resetting,  than  the  value 
of  the  boiler  warrants.  Of  course,  if  permanent,  safe  and  satisfactory 
repairs  are  possible,  no  one  should  object  to  a  patch  of  proper  dimensions, 
properly  applied,  but  the  boiler  maker  should  have  sufficient  judgment 
to  determine  ,and  sufficient  confidence  to  refuse,  if  repairs  should  not  be 
made,  for  otherwise  lives  and  property  are  placed  in  danger. 

LAP  SEAM  CRACK  IN  BOILER  CAUSES  EXPLOSION. 

At  7:30  a.m.,  September  20,  1920,  the  town  of  Antlers,  Okla.,  was 
shocked  by  the  explosion  of  a  boiler  located  in  a  planing  mill  at  that 
place.  The  plant  was  totally  wrecked,  and  two  men  were  killed,  while 
two  others  were  seriously  injured.  The  head  of  one  of  the  men  who 
were  killed  was  completely  severed  from  the  body. 

The  immediate  cause  of  the  explosion  was  a  lap  seam  crack,  which 
extended  from  the  front  head  to  the  rear  head  of  the  boiler,  along  the 


Fig.  2.     View  of  shell  plates,  showing  patch  and  extent  of  crack. 

longitudinal  seam,  and  which  no  doubt  had  been  years  in  fully  develop- 
ing. The  complete  history  of  the  boiler  was  unknown,  but  it  was  said  to 
have  been  purchased  second  hand,  provided  with  usual  safety  appliances, 
and  placed  in  operation  at  100  pounds  pressure,  which  was  continued 
until  leakage  was  observed  at  the  longitudinal  seam  on  the  right  hand 
side,  when  facing  the  front. 

The  home  made  brand  of  calking,  provided  by  those  in  charge,  was 
not  sufficient  to  stop  the  leakage,  so  a  boiler  maker  was  sent  for,  and 
patching  was  determined  upon.  The  patch  can  be  seen  plainly  in  Fig.  2, 
which  also  shows  the  extent  of  the  seam  failure,  and  the  shell  plate 
detached  from  the  heads  and  tubes,  resting  where  it  landed,  about  300 
feet  from  its  original  position. 

Fig.  3  gives  a  close-up  view  of  the  patch,  and  crack  which  extended 
through  the  threaded  holes,  used  in  securing  a  soft  patch,  which  had  been 
applied  by  those  in  charge  of  the  plant. 


4O  BOILER   SAFETY   BULLETIN. 

It  is  possible  that  the  boiler  maker  who  made  the  riveted  patch  repair 
looked  with  pride  upon  his  work,  for  the  patch  was  tight,  and  while  its 
shape  could  have  been  improved  upon,  its  workmanship  was  above  the 
average.  It  is  further  probable  he  had  never  heard  of  a  lap  seam  crack. 
This  is  a  defect  thousands  of  men  are  seeking  daily,  in  order  to  prevent 
just  what  took  place  at  Antlers,  and  if  this  mechanic  had  been  thoroughly 
posted  upon  the  developments  which  have  taken  place  in  his  trade  in 
recent  years,  the  designs  which  have  proven  faulty,  and  the  many  failures 
of  lap  joints,  due  to  the  lap  joint  cracking,  he  could  have  prevented  the 
disaster,  by  refusing  to  make  repairs. 

Many  of  the  states  have  adopted  laws  regulating  the  material,  design, 
construction  and  operation  of  steam  boilers,  but  few  of  them  have  dealt 


Fig.  3.     Close-up  view  of  patch  and  crack. 

extensively  with  rules  controlling  boiler  repairs.  However,  there  is  one 
requirement  which  has  been  almost  universally  adopted,  which  prohibits 
the  repairing  of  a  sheet  in  which  a  lap  seam  crack  has  developed. 

The  A.S.M.E.  Boiler  Code  limits  the  pressure  on  lap  seam  boilers  to 
50  pounds  after  20  years  of  service,  and  likewise  prohibits  repairing 
the  sheet  of  a  boiler  in  which  a  lap  seam  crack  has  been  discovered. 
The  loss  of  life  and  damage  to  property  at  the  Antlers  planing  mill 
alone,  to  say  nothing  of  the  great  number  of  similar  explosions  which 
have  occurred  elsewhere,  clearly  justifies  the  Code  requirements,  and 
every  boiler  maker  called  upon  to  tighten  by  calking,  or  repair  by  patch- 
ing the  longitudinal  seam  of  a  lap  seam  boiler,  should  refuse  to  make 
repairs  until  it  is  clearly  demonstrated  that  a  lap  seam  crack  does  not 
exist.  J.  P.  MORRISON. 


12180     9-21      10M 


14  DAY  USE 

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